Cellulose Decomposition Rates Research Articles

Human activities shape global patterns of decomposition rates in rivers.

Rivers and streams contribute to global carbon cycling by decomposing immense quantities of terrestrial plant matter. However, decomposition rates are highly variable and large-scale patterns and drivers of this process remain poorly understood. Using a cellulose-based assay to reflect the primary constituent of plant detritus, we generated a predictive model (81% variance explained) for cellulose decomposition rates across 514 globally distributed streams. A large number of variables were important for predicting decomposition, highlighting the complexity of this process at the global scale. Predicted cellulose decomposition rates, when combined with genus-level litter quality attributes, explain published leaf litter decomposition rates with high accuracy (70% variance explained). Our global map provides estimates of rates across vast understudied areas of Earth and reveals rapid decomposition across continental-scale areas dominated by human activities.

Interaction among lignocellulosic biomass components in thermochemical processes

This research aims to evaluate the thermal behavior of main components of biomass (hemicellulose, cellulose and lignin) in order to identify their synergistic effect in thermochemical processes. These components were isolated from sugarcane bagasse and straw using different chemical treatments and their chemical and physical-chemical characterizations were performed. Results showed that chemical treatments were adequate for cellulose and lignin isolation, although it was verified that more adequate methodologies must be sought for hemicellulose isolation. The thermogravimetric analysis of each sample and their mixtures in inert (N2) and oxidant (synthetic air) atmospheres allowed investigating the synergism among the components. It was observed that the synergistic effect was more pronounced in DTG curves in an oxidizing atmosphere. There was a weak interaction effect between cellulose and hemicellulose, but hemicellulose allowed reducing cellulose decomposition rate. Moreover, the mixture between hemicellulose and lignin showed a synergistic effect on lignin, which promoted an increase in hemicellulose decomposition rate, while hemicellulose anticipated the main event of lignin decomposition in an oxidizing atmosphere. It was found that lignin had a positive effect on cellulose decomposition in an oxidizing atmosphere, thus inhibiting its decomposition, while cellulose promoted an increase in lignin decomposition rate in its final event. Ultimately, results for the synergistic effect allowed detecting other components besides isolated elements in the biomass structure in smaller amounts, which nevertheless affect the behavior of its thermal decomposition.

Low-active forms of cellulosolitic microorganisms in archaeological contexts

This article presents the results of the study on low-active forms of cellulosolitic microorganisms in the soils of archaeological sites. The objects of the study were soils with traces of wooden structures in Vyatichi burials (12th century). To date, traces of wood are not visible at the macro level. The data obtained are compared with the results of a laboratory experiment to determine rates of cellulose decomposition in soils from various archaeological contexts. Cellulosolitic activity was determined by the application method. It has been shown that the cellulase activity of soils with traces of burial wooden structures is 20% of the level of modern soils. This suggests the awakening or presence of living, low-active microorganisms that have survived in the soil for 800 years.

Exogenous enzyme addition affects litter decomposition by altering the microbial community and litter nutrient content in planted forest

Abstract Litter inputs have great impacts on the soil properties and ecosystem functioning in forests. Rapid litter decomposition leads to decreases in planted forest agricultural waste and enhances the nutrient cycle in forests. The breakdown of litter and the release of various components depend heavily on enzymes. However, the effects of exogenous enzyme preparations on litter decomposition have been hardly investigated. In this study, we examined how these enzymes affected the remaining rate of litter quality, nutrient content (C, N, K), and microbial community diversity. Taking Eriobotrya japonica litter as the research object, five exogenous enzymes (laccase, lignin peroxidase, leucine arylamidase, cellulase, and acid phosphatase) were applied to litter leaves. The mass remaining rate and main nutrient content of the litter were measured during the decomposition period. The microbial diversity attached to the surface of the litter was determined after decomposition at constant temperature and humidity for 189 days. Application of laccase and lignin peroxidase increased litter degradation by affecting microbial diversity, N and K contents. Addition of leucine arylamidase leaded to an increase in N content, and decreased the quality of the litter. The cellulose and lignin decomposition rate in litters was unaffected by the addition of cellulase, laccase, and lignin peroxidase. These results indicate that exogenous addition of enzymes may alter the nutrient content and microbial community, thus affecting litter decomposition. It is imperative to investigate the effects and mechanisms of exogenous enzymes on litter decomposition for regulating decomposition of agricultural waste litter.

Does Spartina invasion affect the carbohydrate assimilation of polychaetes in mangroves? A case study in the Zhangjiang Estuary Mangrove National Nature Reserve

Carbohydrates, which form a large pool of carbon in plant litter, are a major driver of litter dynamics and benthic food webs in Spartina-invaded mangrove ecosystems. However, there are large gaps in knowledge regarding the effects of exotic leaf litter carbohydrates on benthic carbon assimilation. In this study, the dynamics of carbohydrates, including cellulose, lignin and monosaccharides (glucose, mannose, galactose, xylose and arabinose), during the leaf litter decomposition of the exotic Spartina alterniflora (SA) and the native mangrove plant Kandelia obovata (KO) were analyzed and compared. Meanwhile, the differences in the δ13C values of cellulose and lignin were used to analyze the utilization of leaf litter carbohydrates by polychaetes after Spartina invasion. Our results showed that the decomposition rate of exotic SA leaf litter was lower than that of KO leaf litter. The contents of cellulose, glucose and galactose in SA leaf litter were higher than those in KO leaf litter (P < 0.05). The decomposition rates of cellulose and monosaccharides (arabinose, xylose, mannose and galactose) in KO leaf litter were faster than those in SA leaf litter (P < 0.05). However, there was no significant difference in the decomposition rates of lignin in the leaf litter between exotic SA leaf litter and native KO leaf litter (P > 0.05). In the native KO plot, the carbohydrates of KO leaf litter contributed to >55% (cellulose, 26.91–28.02%; lignin, 28.05–28.64%) of the organic carbon sources of polychaetes. However, in the exotic SA plot, the carbohydrates of exotic SA leaf litter contributed to >65% (cellulose, 36.83–38.30%; lignin, 28.47–30.52%) of the organic carbon sources of polychaetes. The obtained results suggested that Spartina invasion increased the assimilation of cellulose by polychaetes. The high content and low decomposition rate of cellulose in the carbohydrates of exotic SA leaf litter might be important mechanisms for the carbon assimilation changes in the benthos of Spartina-invaded mangrove ecosystems. Given that Spartina has colonized in the Zhangjiang Estuary Mangrove Reserve, this study provides a theoretical basis for the recovery of benthos after ecological restoration. Furthermore, the mechanisms of carbohydrate assimilation by different benthos of different ecosystems should be comprehensively considered in the future.

Effects of UV-B Radiation on the Chemical Composition of Azolla and Its Decomposition after Returning to the Field and Nitrogen Transformation in Soil

In the present research, the effects of UV-B radiation (5.00 kJ·m−2) on the chemical composition of Azolla were investigated, and the decomposition of Azolla residues after UV-B radiation, the nitrogen form, enzyme activity, and bacterial community in paddy soil were analyzed. Compared to the natural light treatment, the total nitrogen content of Azolla was significantly increased by 17.0% under UV-B radiation treatment. Compared to returned Azolla grown under natural light, the decomposition rate of cellulose, lignin, and total nitrogen of returned Azolla grown under UV-B radiation significantly increased, which led to an increase in the activities of nitrogen transformation enzymes, including neutral protease, ammonia monooxygenase, nitrogenase, nitrate reductase, and nitrite reductase, and the contents of different nitrogen forms (NH4+-N, NO3−-N, soluble organic nitrogen, and microbial biomass nitrogen) in paddy soil, while N2O emission flux was significantly reduced by 20–30%. The dominant bacteria in soil supplied with Azolla grown under natural light were Firmicutes, Clostridia, Clostridiales, and Lachnospiraceae. However, returning Azolla grown under UV-B radiation to the soil significantly changed the bacterial community structure in soil, resulting in a decrease in the number of ammonifying bacteria, nitrifying bacteria, and nitrogen-fixing bacteria and an increase in the number of denitrifying bacteria, inducing changes in the dominant bacteria to Methanomicrobiales, Methanoregulaceae, and Methanoregula. According to the structural equation model, returning Azolla to the field would reduce N2O emissions by increasing Azolla lignin decomposition and ammonia monooxygenase activity, reducing the number of nitrifying bacteria and reducing nitrite reductase activity in soil. Thus, UV-B radiation can directly change the phytochemical components and their decomposition in soil, thus indirectly affecting the bacterial community structure, enzyme activity, and nitrogen transformation, which play important ecological roles in regulating the nutrient transformation of terrestrial ecosystems.

Deep Straw Burial Accelerates Straw Decomposition and Improves Soil Water Repellency

The continuous input, slow decomposition, and retention of straw can impede tillage and crop growth, and the decomposition process of the straw in soil is affected by its composition and the method of application. Experimental Station of Jilin Agricultural University, Changchun City, Jilin Province. The soil type was Argiudolls, the experimental field area was 30 m2, and the maize was planted continuously for 12 years without returning the straw to the field. There were four treatments: (1) control (CK), 10 g of straw was placed on the surface of a nylon mesh bag, and the nylon mesh bag was separated from the soil by polyethylene film without contacting with the soil; (2) straw mulching (CM), a nylon mesh bag with 10 g of straw was placed on the soil surface; (3) straw burying (CD), a nylon mesh bag with 10 g of straw was buried at a depth of 40 cm from the soil surface; (4) straw burying (CE), a nylon mesh bag with 40 cm of soil depth. Fifteen micro-zones were set up with a micro-zone area of 1 m2 and each micro-zone consisted of four treatments randomly grouped in three replicates per treatment. The on-site nylon bag burying trial started on 20 April 2021 and ended on 15 April 2022. Nylon bag and soil samples were collected on days 0, 30, 90, 180, 270, and 360. SOC, TN, straw component decomposition, and water droplet-soil contact angle were determined. Our results showed that the CE treatment increased soil organic carbon (SOC) and total nitrogen (TN) content compared to the CM and CD treatments. Compared with CK, straw decomposition rates increased by 13.3%, 30.8%, and 22.3% in the CM, CD, and CE treatments, respectively. Lignin decomposition rates increased by 7.8%, 27.3%, and 16.2%; cellulose decomposition rates increased by 14.6%, 35.4%, and 27.3%; and hemicellulose decomposition rates increased by 17.2%, 31.7% and 23.7% in the CD treatment, respectively. Compared with CK, the contact angle of droplets in the CD treatment was statistically significantly increased by 91.5% when the droplets remained on the soil surface for 5 s. The rate of decrease of droplet contact angle with time was statistically significantly decreased by 11.8%, and the penetration rate of droplets on the soil surface was slower. Overall, the CD treatment promoted straw decomposition and increased SWR compared to the CM and CE treatments. which are important attributes to enhance soil quality and improve soil structural stability.

The Influence of Logging Equipment on the Content, Stock and Stratification Coefficient of Elements of the Mineral Nutrition of Plants in the Soils of the Taiga Zone of Karelia

This study was carried out in the territories of Northern Europe, in the middle taiga subzone of Karelia. The paper presents the results of a study of an experiment on logging to study the impact of controlled logging using supervised logging with controlling cutting (SLCC) and conventional logging (CL) on the properties of soils (horizons O, E and BF) in a spruce forest 15 years after logging. Virgin forest (VF) was used as a control. The volume weight of soils, the contents of carbon, nitrogen and potassium in different soil layers (layers O, E and BF), as well as reserves of C, N and K and their stratification coefficients SRs (SR1 [O:E], SR2 [O:BF] and SR3 [E:BF]) were studied. The results showed a tendency to increase the volume weight of soils of anthropogenically disturbed (CL and SLCC) areas can be measured. The obtained data demonstrated that there was no sharp change in the contents or stocks of the studied elements between the anthropogenically disturbed (CL and SLCC) and undisturbed areas (VF). The largest reserves of carbon, nitrogen and potassium were noted in the upper horizons of the soils of all sites, averaging 35.6, 1.27 and 0.073 t/ha, respectively. In the lower horizons of the studied soils, the values were lower. The values of the stratification coefficients in the studied soils were arranged in decreasing order as SR2 &gt; SR1 &gt; SR3. At the same time, the general trend of unidirectional changes in the SR values for carbon and potassium in soils was noted; the data for nitrogen were somewhat different. The results showed a marked decrease in SOC concentration with an increase in soil depth. Higher rates of cellulose decomposition were observed in anthropogenically disturbed areas (CL—69.0 ± 3.6%; SLCC—57.4 ± 3.5%) compared with virgin forest (VF) (53.7 ± 3.1%), which is consistent with the results of other studies in the taiga zone. The data obtained indicate the importance of a more accurate assessment of the contents and stocks of elements, as well as the need to use tests for soil biological activity.

Solid tailings after supercritical CO&lt;sub&gt;2&lt;/sub&gt; extraction of lignocellulosic biomass as a source of quality biochar for energetic use and as soil improvement

Lignocellulosic biomass is a rich source of bioactive compounds that are extracted industrially from different parts of the plant. The extraction process generates residues that can contain from 75% to 95% of the raw material depending on the species. Among the many potential products of post-extraction residue’ processing there is biochar. The research objective was: i) to evaluate the parameters of biochars derived from post-extraction bark, wood and bark and wood of four lignocellulosic species; and ii) to discuss the parameters in the context of biochar functionality as an energy carrier and soil improver. The residues were subjected to pyrolysis at the three temperatures 170, 270, and 370°C, which correspond to the initiation of carbonization, and two biochars that differ in the decomposition rates of hemicelluloses, cellulose and lignin. On average, biochars had a high energy value owing to the increased content of the total and fixed carbon and calorific value by 77.0-78.4% DM, 64.6-66.7% DM and 25.8-30.1 MJ kg–1, respectively. The higher quantity of ash after processing of bark residues than wood residues implicates a lower energy value but at the same time the ash obtained is a better source of mineral compounds in the context of soil fertilization. Concerning the use of biochar as a soil improver, the biochars demonstrated lower H/C and O/C molar ratios, that indicate raised stability and resistance to the geochemical decomposition in soil. It was proven that the bark-based biochars had much higher concentrations of micro- and macronutrients as well as a higher pH, while processed wood fractions resulted in higher concentrations of total carbon and fixed carbon in biochar. The research results suggest that lignocellulose biomass extraction residues can serve as a valuable input material for production of biochar.

Plant material decomposition and bacterial and fungal communities in serpentine and karst soils of Japanese cool-temperate forests

ABSTRACT We aimed to reveal the plant material decomposition rate and abundance of bacteria and fungi in serpentine and karst sites of cool-temperate forests. Given the relatively higher soil pH, we hypothesized a higher decomposition rate of cellulose, lower decomposition rate of lignin-containing plant materials, and lower fungi-to-bacteria ratio in serpentine and karst sites than in neighboring non-serpentine/non-karst sites. This study was conducted on serpentine and mudstone sites in deciduous oak forests on Mount Oe and karst and sandstone sites on Mount Ibuki, Japan. We performed a decomposition experiment over 5 months using three chemically distinct materials: cellulose filter, lignin-containing coffee filter, and green tea leaves. These common materials enabled us to compare the in-situ utilization of different carbon substrates by microbial communities between sites. The abundance of bacteria and fungi and their ratio in topsoils and materials that decomposed for 1 month were assessed using quantitative PCR. In contrast to our hypothesis, the decomposition rate was higher in the mudstone site for cellulose and did not differ for the coffee filter compared to the serpentine site. Green teas with higher lignin content than coffee filters decomposed slower at the serpentine site only during the early period of decomposition. The serpentine site showed higher fungi-to-bacteria ratios in the decomposed materials and soil. The karst site also showed different decomposition patterns than our prediction, presenting no clear difference in the cellulose filter compared to the sandstone site. In the karst site, coffee filters decomposed faster at the early period; however, green teas decomposed slower as we expected, especially at the later period of decomposition. The karst site had a lower fungi-to-bacteria ratio in the topsoil, but similar fungi-to-bacteria ratios in the decomposed materials compared with the sandstone site. Our results suggest that the decomposition patterns in the serpentine and karst soils are not simply predicted based on soil pH and other distinct characteristics (e.g., soil moisture content and heavy metal concentration) would more strongly contribute to decomposition and microbial community composition in the study mountains.

Decoupling of cellulose decomposition and glucose mineralization in volcanic forest soils

ABSTRACT Decomposition of organic matters in volcanic soils (ando soils) is generally slowed by sorption onto short-range-order minerals, while decomposition of non-charged substrates such as cellulose and glucose is hypothesized to be promoted by high microbial biomass and nitrogen availability, irrespective of short-range-order minerals. To analyze factors regulating decomposition activities of cellulose and glucose, we measured the decomposition rates of cellulose filter papers and the mineralization rates of 14C-labeled glucose in five volcanic soils in Japan. Glucose mineralization activities increased with increasing microbial biomass C and N, while cellulose decomposition activities (standardized with cumulative temperature) were not related to microbial biomass C or N. Cellulose decomposition activities increased with increasing ratio of soil available N relative to microbial biomass N (microbial N availability), while they decreased with decreasing soil pH and with increasing fungal activities. Soils with relatively high soil pH and microbial N availability exhibit the relatively high potentials of cellulose decomposition. Because cellulose decomposition, rather than glucose mineralization, is a rate-limiting step, soil pH and microbial N availability, rather than microbial biomass, could primarily regulate decomposition rates of cellulose and glucose in volcanic soils.

ASSESSMENT OF THE EFFECT OF BIOCHAR ON THE PROCESS OF THERMOLISIS OF BIOMASS OF PLANTS GROWN ON RECLAIMED LANDS

Samples of soil contaminated with heavy metals for pot experiments with annual crops (maize, sweet and sudan sorghum) were taken near the mines "Pavlogradska" and "Blagodatna" in the coal-mining region of Western Donbass. The basis of the reclaimed areas was an 8-10 m thick mine rock (MR) dump, covered with different layers of black soil or red-brown clay by creating two types of soil artificial profiles with the addition of 30 cm of black soil (30 cm of BS +MR) and 50 cm red-brown clay (50 cm RBC + MR). Experimental soil samples were treated with 3.0% (w/w) biochar. The purpose of the study was to study the effect of the addition of biochar on the process of thermal destruction of the biomass of maize, sweet and sudan sorghum, grown on different substrates - components of artificial reclaimed profiles (upper layers of chernozem mass and red-brown clay). The process of thermolysis of biomass components of three agricultural crops was studied by the method of thermogravimetric analysis. Thermal destruction of the biomass of the three studied plant species occurred in two stages: evaporation of water and volatile compounds (stage 1) and decomposition of the main components: hemicellulose, cellulose and lignin (stage 2). The first stage took place in the temperature range of 50-180°С. The process was slow, the maximum speed did not exceed 5-8%/min, the extreme point was observed at a temperature of 100-110°C. Loss of body weight is insignificant, 4.5–7.5%. The second stage is divided into two phases: the decomposition of holocellulose with the beginning of lignin decomposition (phase 1) and the cessation of lignin decomposition, and the formation of non-combustible residue (phase 2). Destruction of holocellulose occurred in the temperature range of 190-390°С. Due to the large amount of hemicellulose in the biomass of the studied plants, its decomposition was shifted to the region of higher temperatures. Therefore, the degradation ranges of hemicellulose and cellulose overlapped, and only one extreme point was observed in the DTG curves. The process proceeded at high speeds with the peak of destruction in the temperature range of 280-310°C. Weight loss was also the most significant and was between 50 and 55%. Decomposition of lignin occurred rather slowly, with one insignificant peak in the temperature range of 420-440°C. A weight loss of 26-30% has been established. At the first stage, the process proceeded mainly with heat absorption; the reactions of the second stage were exothermic with noticeable thermal effects in the zones of cellulose and lignin decomposition. Differences in thermal characteristics of sugar sorghum biomass grown on different substrates and with the addition of biochar were determined in the process of thermolysis. Degradation of holocellulose occurred more slowly in biomass collected from a vessel with red-brown clay, in contrast to lignin, which decomposed faster than in the experiment where the substrate was a loose layer of chernozem. The share of non-combustible residues was almost 2 times smaller. A slight increase in the rate of the cellulose decomposition reaction (1,2 times) and a significant increase in the rate of the lignin destruction reaction (5 times) was observed. In the treatment with biochar, a more complete combustion of biomass was observed. The rate of cellulose decomposition in the experiment with red-brown clay became somewhat higher, although the decomposition of lignin occurred more slowly. The share of non-combustible residues increased by 1,8 times. Thermal destruction of Sudan grass biomass on both substrates occurred in a similar manner. The addition of biochar did not reveal significant deviations in the thermal behavior of biomass grown on chernozem, in contrast to the experiment with red-brown clay, where the addition of biochar contributed to a significant reduction in the duration of thermolysis. The first stage of thermolysis of corn biomass was somewhat shorter in the experiment with a bulk layer of chernozem compared to red-brown clay and was accompanied by a lower mass loss. The same trend was observed in the decomposition of holocellulose. At the same time, the destruction of lignin in the version with chernozem lasted longer, the extremum point was shifted to the region of higher temperatures, the speed of the process was almost twice as low as in the version with clay, and the proportion of non-combustible residue was 1,7. times higher. More complete combustion of corn biomass was also observed in the version with biochar.

Impacts of thinning activities on boreal peatland forests

Boreal peatland forests are an important source of timber. Recently, timber harvesting has been extended to warmer months, resulting in machinery traffic over unfrozen soils, and leading to higher levels of soil disturbance, such as deeper ruts. Despite this, our knowledge of the impact of soil disturbance on peat physical properties and soil biochemistry is still limited. To address this gap, I conducted a study to examine the effects of soil disturbance caused by harvesting machinery during thinning operations on the soil physical, chemical, and biological properties and vegetation of drained boreal peatland forests. To assess the rate of recovery, I sampled six sites that formed a chronosequence covering 15 years since thinning. The results showed that soil disturbance caused an increase in the bulk density and field capacity of peat, along with a decrease in total porosity. In the vegetation, moss biomass and root production were reduced, but sedge cover increased. Furthermore, recently disturbed areas exhibited greater soil CO2 production potential, as well as higher soil CO2 and CH4 concentrations compared to control areas. However, CO2 and CH4 emissions, microbial communities, and cellulose decomposition rate were not impacted. Although the rate of recovery varied, all studied properties impacted by disturbance were fully recovered within 15 years. As the water retention characteristic (WRC) describes soil structure and its alterations, it a useful for disturbance assessment. Thus, I propose how WRC can be predicted using artificial neural networks. Overall, the study demonstrated that while drained boreal peatlands are sensitive to disturbance, they are also resilient to mechanical soil disturbance caused by thinnings.

Keystone microbial taxa drive the accelerated decompositions of cellulose and lignin by long-term resource enrichments

Lignin and cellulose are the most important component of crop straw entering arable soil. The decomposition of lignin and cellulose are related to carbon sequestration and soil fertility. The keystone microbes decomposing lignin and cellulose in cropland and their impact on agricultural management, however, remains largely unclear. In this study, we traced the carbon (C) from highly enriched 13C-labeled (atom% 13C = 99 %) lignin and cellulose to functional keystone microbes in soils of a 26-year fertilization field experiment with stable isotope probing (SIP). 13C-cellulose and 13C-lignin decomposition were significantly accelerated with the long-term application of fertilization, especially with the combination of organic and chemical fertilization (NPKM). The 13C was mainly assimilated by bacteria Acidobacteria (i.e. GP1, GP3, GP6), Proteobacteria (i.e. unidentified gamaproteobactiera, Bradyrhizobium), and fungi Ascomycota (i.e. Talaromyces and Fusarium, etc.). The keystone bacteria taxa decomposing cellulose and lignin were large overlapped, but substantially shaped by fertilization. For instance, GP3 was the dominant bacterium that decomposed both cellulose and lignin in no fertilizer control (CK), while GP1 and GP6 were the ones in chemical fertilization (NPK) and NPKM, respectively. The decomposition rates of cellulose in different fertilizations were majorly predicted by soil total phosphorus (TP), functional fungi abundance, total nitrogen (TN), whereas functional bacterial and fungal abundance, TP, and community structure of functional fungi manipulated the decomposing rate of lignin. Together, we demonstrate that keystone functional microbes decomposing cellulose and lignin were largely concurring and significantly altered by long-term resources enrichment, which drives the similar patterns of decomposition rates of these two substrates along the resource enrichment gradient.

Application of Additives in Platycladus orientalis (L.) Franco Tending Shreds Compost in Forest

This study aimed to explore the effects of different additives on tending shreds of Platycladus orientalis (L.) Franco. Two different additives (priming 0.2% and common compost 0.2%) combined with C, N, and P adjustment of raw material treatments were tested on the temperature, moisture, EC, pH, lignocellulose degradation rate, nutrient content, and toxicity of compost. Priming made the compost temperature rise rapidly, and the peak temperature of the composting group with priming reached 51 °C. At the end of composting, the moisture in each treatment from high to low was in the order: common compost &gt; priming &gt; C/N, C/P adjustment only &gt; control group. The increase of EC in the treatments with additives was great, and the peak value of EC in the treatment of priming was 1.30 ms·cm−1, which was 3.9 times higher than that of the control group. At the end of composting, the decomposition rate of cellulose in priming compost was 1.7 times higher than that in the control group, and the hemicellulose decomposition rate in the common compost group was 3.2 times higher than that in the control group. By the end of composting, the pH value of the composts in additive treatments was above 7.0, and the pH value of the priming treatment was the highest (7.5). The highest content of organic matter was found in the priming treatment, which was 52%, 1.7 times higher than that in the control group. The total nutrient content (TN + K2O + P2O5) of additive treatments was higher than 5.0%, and the priming treatment was 2.7% higher than that of the control group. By the end of composting, the germination rate and germination index ranged from 88% to 91% and 60% to 81%. Except for the control group, the C/N ratio of other treatments decreased to below 25. Additives can accelerate the decomposition of raw materials, shorten the composting cycle, and improve the quality of composts, and the effect of adding priming is the most significant.

Protocol of conjugate evaluation of the biological activity of soils in terms of cellulolytic activity and biological consumption of oxygen

The article presents protocols for determining the biological activity of kerosene-contaminated soils in terms of two indicators, i.e. cellulolytic activity and biological consumption of oxygen. A method for determining the cellulolytic activity of soils is based on measuring the rate of cellulose decomposition in situ. Model test objects (linen fragments 10 × 20 cm weighing 4–6 g) were put in the root layer of soil. A month later, the linen was removed from soil and its weight loss was measured. Cellulolytic activity was estimated by the weight loss of readily hydrolysable organic matter (RHOM) per day (mg/g RHOM per day). The method for determining the biological consumption of oxygen of water was adapted for soils. The indicator characterizes the ability of microorganisms to oxidize organic substances using oxygen for 5 days. The analytic procedure includes taking a soil sample, preparing the suspension (the ratio of soil to distilled water is at least 1:10) and after 5 days measuring the concentration of unspent dissolved oxygen using the oxygen meter. The proposed methods give reproducible and reliable results on the biochemical activity of soil microorganisms in a wide range of soils, e.g. Retisols, Arenosols and Histosols, including those under hydrocarbon pollution.

Response of vegetation and soil biological properties to soil deformation in logging trails of drained boreal peatland forests

In the boreal region, peatland forests are a significant resource of timber. Under pressure from a growing bioeconomy and climate change, timber harvesting is increasingly occurring over unfrozen soils. This is likely to cause disturbance in the soil biogeochemistry. We studied the impact of machinery-induced soil disturbance on the vegetation, microbes, and soil biogeochemistry of drained boreal peatland forests caused by machinery traffic during thinning operations. To assess potential recovery, we sampled six sites that ranged in time since thinning from a few months to 15 years. Soil disturbance directly decreased moss biomass and led to an increase in sedge cover and a decrease in root production. Moreover, soil CO2 production potential, and soil CO2 and CH4 concentrations were greater in recently disturbed areas than in the control areas. In contrast, CO2 and CH4 emissions, microbial biomass and structure, and the decomposition rate of cellulose appeared to be uncoupled and did not show signs of impact. While the impacted properties varied in their rate of recovery, they all fully recovered within 15 years covered by our chronosequence study. Conclusively, drained boreal peatlands appeared to have high biological resilience to soil disturbance caused by forest machinery during thinning operations.

Composition of microorganisms in carbonated mineral waters of the Mukhen deposit (Khabarovsk territory)

The chemical composition, distribution, structure, number of physiological groups of cultivated bacteria and their biodiversity in the cold carbonic mineral waters of Mukhen and in microbial mats were studied. It is shown that the mineral waters are cold, hydrocarbonate-calcium-magnesium, enriched with iron, manganese, barium. Carbon dioxide predominates in the gaseous composition of waters. Microbiological studies have shown that no sanitary-indicative microflora was found in mineral waters, which indicates the purity of underground waters. Carbonic waters were characterized by a low number of physiological groups of autochthonous bacteria. Among the studied microorganisms, chemolithotrophic thionic bacteria predominated, which indicates the predominance of oxidation processes of reduced sulfur compounds with the participation of bacteria in groundwater. In the microbial mats, various chemolithotrophic and heterotrophic microorganisms were identified, participating in the geochemical cycles of carbon, nitrogen, sulfur, iron, manganese, and silicon. The number of physiological groups of bacteria was higher than in mineral waters, along with this saprophytic bacteria predominated significantly. A sufficiently high rate of protein and cellulose decomposition by microorganisms of microbial mats was shown. A low diversity of cultured heterotrophic bacteria with the dominance of microorganisms of the genus Bacillus was found in mineral waters and in microbial mats. By using the methods of X-ray phase analysis, the important role of microorganisms of microbial mats in the precipitation of silicate minerals and the formation of calcium carbonates was shown.

Increased enzyme activities and fungal degraders by Gloeophyllum trabeum inoculation improve lignocellulose degradation efficiency during manure-straw composting

The present study investigated the effect of brown-rot fungus Gloeophyllum trabeum inoculation on lignocellulose degradation, enzyme activities and fungal community during co-composting of swine manure and wheat straw. G. trabeum inoculation shortened the maturation period of composting from 39 to 30 days. Composting piles inoculated with G. trabeum showed a higher degree of maturity as indicated by 31.6% lower C/N ratio and 29.4% higher GI. The decomposition rate of cellulose, hemicellulose and lignin was increased by 181.1%, 49.4% and 109.4%, respectively, due to higher activities of filter paper enzyme, xylanase, manganese peroxidase and laccase. Redundancy analysis showed that inoculating G. trabeum influenced the succession of fungal communities by changing the main physicochemical parameters, resulting in the increased relative abundance of Aspergillus, Mycothermus and Melanocarpus. Pearson correlation analysis indicated that more dominant fungal genera were involved in the production of lignocellulose-degrading enzymes after G. trabeum inoculation.

A sustainable production of lignocellulolytic enzymes and value added metabolites from banana pseudostem waste by Bacillus wakoensis NAULH-4

The most plentiful carbohydrate present on earth is in the form of cellulose which has a tremendous capacity to manufacture second or third-generation biofuels and other valuable metabolites. Cellulose is a significant part of banana pseudostem (BP) squander that causes numerous environmental issues. Hence, disposal of BP is nowadays a major obstacle for Indian farmers because of immense volume, delay in decay raise in a foul smell during debasement which attracts pests and insects to farm. The present study reports the identification of potential isolates, which efficiently debase BP. Out of many isolates, NAULH-4 showed the uppermost decomposition rate of cellulose, hemicellulose, and lignin at 45 °C and pH 8 up to 28 days incubation. Moreover, the taxonomic characterization using phenotypic microarray (PM) technology directs that the isolate NAULH-4 belongs to Bacillus with 0.71 SIM index in metabolic pathway network which is reinforced by 16 s rRNA analysis. Molecular data reveal that NAULH-4 contain laccase, xylanase, and cellulase gene. Overall, Bacillus wakoensis NAULH-4 can be applicable for promising microbe for the conversion of BP waste into value-added metabolites.