Hemicellulose Content Research Articles

Phytoremediation of copper-contaminated soils by rapeseed (Brassica napus L.) and underlying molecular mechanisms for copper absorption and sequestration

High levels of copper released in the soil, mainly from anthropogenic activity, can be hazardous to plants, animals, and humans. The present research aimed to estimate the suitability and effectiveness of rapeseed (Brassica napus L.) as a possible soil remediation option and to uncover underlying adaptive mechanisms A pot experiment was conducted to explore the effect of copper stress on agronomic and yield traits for 32 rapeseed genotypes. The copper-tolerant genotype H2009 and copper-sensitive genotype ZYZ16 were selected for further physiological, metabolomic, and transcriptomic analyses. The results exhibited a significant genotypic variation in copper stress tolerance in rapeseed. Specifically, the ratio of seed yield under copper stress to control ranged from 0.29 to 0.74. Furthermore, the proline content and antioxidant enzymatic activities in the roots were greater than those in the shoots. The accumulated copper in the roots accounted for about 50% of the total amount absorbed by plants; thus, the genotypes possessing high root volumes can be used for rhizofiltration to uptake and sequester copper. Additionally, the pectin and hemicellulose contents were significantly increased by 15.6% and 162%, respectively, under copper stress for the copper-tolerant genotype, allowing for greater sequestration of copper ions in the cell wall and lower oxidative stress. Comparative analysis of transcriptomes and metabolomes revealed that excessive copper enhanced the up-regulation of functional genes or metabolites related to cell wall binding, copper transportation, and chelation in the copper-tolerant genotype. Our results suggest that copper-tolerant rapeseed can thrive in heavily copper-polluted soils with a 5.85% remediation efficiency as well as produce seed and vegetable oil without exceeding food quality standards for the industry. This multi-omics comparison study provides insights into breeding copper-tolerant genotypes that can be used for the phytoremediation of heavy metal-polluted soils.

Variation of mesophyll conductance mediated by nitrogen form is related to changes in cell wall property and chloroplast number.

Plants primarily incorporate nitrate (NO3 -) and ammonium (NH4 +) as the primary source of inorganic nitrogen (N); the physiological mechanisms of photosynthesis (A) dropdown under NH4 + nutrition has been investigated in many studies. Leaf anatomy is a major determinant to mesophyll conductance (g m) and photosynthesis; however, it remains unclear whether the photosynthesis variations of plants exposed to different N forms is related to leaf anatomical variation. In this work, a common shrub, Lonicera japonica was hydroponically grown under NH4 +, NO3 - and 50% NH4 +/NO3 -. We found that leaf N significantly accumulated under NH4 +, whereas the photosynthesis was significantly decreased, which was mainly caused by a reduced g m. The reduced g m under NH4 + was related to the decreased intercellular air space, the reduced chloroplast number and especially the thicker cell walls. Among the cell wall components, lignin and hemicellulose contents under NH4 + nutrition were significantly higher than those in the other two N forms and were scaled negatively correlated with g m; while pectin content was independent from N forms. Pathway analysis further revealed that the cell wall components might indirectly regulate g m by influencing the thickness of the cell wall. These results highlight the importance of leaf anatomical variation characterized by modifications of chloroplasts number and cell wall thickness and compositions, in the regulation of photosynthesis in response to varied N sources.

A Network of Processes for Biorefining Burdock Seeds and Roots.

In this work, a novel sustainable approach was proposed for the integral valorisation of Arctium lappa (burdock) seeds and roots. Firstly, a preliminary recovery of bioactive compounds, including unsaturated fatty acids, was performed. Then, simple sugars (i.e., fructose and sucrose) and phenolic compounds were extracted by using compressed fluids (supercritical CO2 and propane). Consequently, a complete characterisation of raw biomass and extraction residues was carried out to determine the starting chemical composition in terms of residual lipids, proteins, hemicellulose, cellulose, lignin, and ash content. Subsequently, three alternative ways to utilise extraction residues were proposed and successfully tested: (i) enzymatic hydrolysis operated by Cellulases (Thricoderma resei) of raw and residual biomass to glucose, (ii) direct ethanolysis to produce ethyl levulinate; and (iii) pyrolysis to obtain biochar to be used as supports for the synthesis of sulfonated magnetic iron-carbon catalysts (Fe-SMCC) to be applied in the dehydration of fructose for the synthesis of 5-hydroxymethylfurfural (5-HMF). The development of these advanced approaches enabled the full utilisation of this resource through the production of fine chemicals and value-added compounds in line with the principles of the circular economy.

Effect of lignocellulosic biomass components on the extracellular electron transfer of biochar-based microbe-electrode in microbial electrochemical systems

Biomass-derived carbon-based electrodes with good biocompatibility, sustainability, and low cost are competitive in microbial electrochemical systems. Unfortunately, biomass composition is complex, and biochar performance is dependent on the kind of biomass, making quantitative function control difficult. Three-dimensional (3D) lignocellulosic carbon-based electrodes were generated in this study by varying the ratios of three natural biopolymers (cellulose, lignin, and hemicellulose). The biopolymer contents significantly impacted the material's physicochemical and electrochemical properties. Only the proper ratio of these natural polymers can ensure the 3D structure's integrity and mechanical strength after carbonization. The greater the cellulose content and the lower the hemicellulose (xylan) content, the lower the ohmic and charge transfer resistance. The maximum power density (Pmax) of the microbial fuel cells equipped with the biopolymer-based anode ranged between 4.5 and 4.8 W m−2, setting a new record for biocarbon electrodes. The highest Pmax was observed when the cellulose, lignin, and xylan ratios were 1:3:2 (4.80 ± 0.04 W m−2). The Pmax correlates with cellulose content more than lignin and xylan and with material capacitance more than with other parameters. High cellulose content facilitates electron transfer but reduces the capacitance of carbon-based electrodes. The material's electron transfer resistance and capacitance contribute to the opposite of the Pmax. So, the interaction with multiple properties influences the electrode performance. This research revealed the effects of natural biopolymer compositions on electrode performance, which was helpful for quantitatively modifying functional carbon-based materials.

Catalytic Supercritical Water Gasification of Canola Straw with Promoted and Supported Nickel-Based Catalysts.

Lignocellulosic biomass such as canola straw is produced as low-value residue from the canola processing industry. Its high cellulose and hemicellulose content makes it a suitable candidate for the production of hydrogen via supercritical water gasification. However, supercritical water gasification of lignocellulosic biomass such as canola straw suffers from low hydrogen yield, hydrogen selectivity, and conversion efficiencies. Cost-effective and sustainable catalysts with high catalytic activity for supercritical water gasification are increasingly becoming a focal point of interest. In this research study, novel wet-impregnated nickel-based catalysts supported on carbon-negative hydrochar obtained from hydrothermal liquefaction (HTL-HC) and hydrothermal carbonization (HTC-HC) of canola straw, along with other nickel-supported catalysts such as Ni/Al2O3, Ni/ZrO2, Ni/CNT, and Ni/AC, were synthesized for gasification of canola straw on previously optimized reaction conditions of 500 °C, 60 min, 10 wt%, and 23-25 MPa. The order of hydrogen yield for the six supports was (10.5 mmol/g) Ni/ZrO2 > (9.9 mmol/g) Ni/Al2O3 > (9.1 mmol/g) Ni/HTL-HC > (8.8 mmol/g) Ni/HTC-HC > (7.7 mmol/g) Ni/AC > (6.8 mmol/g) Ni/CNT, compared to 8.1 mmol/g for the non-catalytic run. The most suitable Ni/ZrO2 catalyst was further modified using promotors such as K, Zn, and Ce, and the performance of the promoted Ni/ZrO2 catalysts was evaluated. Ni-Ce/ZrO2 showed the highest hydrogen yield of 12.9 mmol/g, followed by 12.0 mmol/g for Ni-Zn/ZrO2 and 11.6 mmol/g for Ni-K/ZrO2. The most suitable Ni-Ce/ZrO2 catalysts also demonstrated high stability over their repeated use. The superior performance of the Ni-Ce/ZrO2 was due to its high nickel dispersion, resilience to sintering, high thermal stability, and oxygen storage capabilities to minimize coke deposition.

Enhancing the dispersibility of Gelidium amansii-derived microfibrillated cellulose through centrifugal fractionation

Hydrothermal pretreatment is useful for microfibrillated cellulose (MFC) preparation due to its safety, but the remaining hemicellulose might affect MFC properties. This study aimed to investigate the effect of centrifugation time on hemicellulose removal and the physicochemical properties of MFC obtained after hydrothermal pretreatment and micro-fibrillation. In this study, centrifugation was applied to the MFC suspension at varying duration times. Composition analysis and Fourier transform infrared spectra indicated that fractionated MFC has no hemicellulose content after 10, 20, and 30 min centrifugation. It also showed an approximately 5 times higher than 0.5 % g/g of initial solid concentration, indicated by a lower gel concentration point, than unfractionated MFC. Scanning electron microscope images of the fractionated MFC for 30 min (MFC2C) presented thin, long cellulose fibrils of 517 nm in average diameter and 635–10,000 nm in length that induced a slower sedimentation rate. MFC2C dispersion was also improved by autoclave sterilization by regulating cellulose structure, rheology, and crystallinity. As a result, MFC dispersibility can be enhanced by removing hemicellulose through simple centrifugation.

Extraction and characterization of hemicellulose and lignin contents of areca fiber

Extraction and characterization of hemicellulose and lignin contents of areca fiber

Rice straw anaerobic co-digestion: Comparing various pre-treatment techniques to enhance biogas production

Study investigates rice straw size impact on co-digestion with four pre-treatments: thermal, hydrogen peroxide, combined thermal and hydrogen peroxide, and hydrogen peroxide followed by thermal treatment. Rice straw is divided into four sizes: 3–5 cm, 1–2 cm, 5–10 mm, and 300 μm. Co-substrates, sewage sludge, and chicken manure are used at a 20 % total solids concentration. Pre-treatment effects on rice straw and volatile fatty acid content post-digestion are assessed by quantifying cellulose, hemicellulose, and lignin content. Thermal pre-treatment, particularly on 1–2 cm-sized rice straw, demonstrates the highest efficacy with biogas production of 389 mL/g-VS. Preferred rice straw sizes for adaptability are ranked: 1–2 cm > 5–10 mm > 3–5 cm > 300 μm. However, pre-treatment fails to enhance biogas production compared to the control, attributed to structural deterioration, accelerated hydrolysis, elevated VFA levels, methanogenic inhibition, and increased hemicellulose content. Co-digestion is recommended over pre-treatment for rice straw anaerobic digestion.

Identification and Gene Cloning of a Brittle Culm Mutant (bc22) in Rice

The mechanical strength of rice culm, an essential factor for lodging resistance and yield maintenance, is influenced by the composition and structure of the cell wall. In this study, we characterized a rice brittle culm mutant 22 (bc22), derived from LR005 through ethyl methanesulfonate (EMS) mutagenesis. The bc22 culm exhibited increased fragility and reduced mechanical strength compared to LR005. The mutant displayed pleiotropic effects, including a shorter plant height and panicle length, a smaller grain size, and the absence of the glume hairs. Scanning electron microscopy revealed a decrease in cell density and a looser structure in the bc22 culms. Biochemical analysis demonstrated a significant increase in hemicellulose content and a marked reduction in lignin content in the culm of bc22. Genetic analysis indicated that the brittle culm trait was governed by a single recessive gene. After employing bulked segregant analysis (BSA), whole-genome resequencing, and MutMap methods, LOC_Os02g25230 was identified as the candidate gene responsible for bc22. In bc22, a point mutation from proline (Pro) to leucine (Leu) in its coding region led to the pleiotropic phenotype. A complementation test further confirmed that the missense mutation causing the proline to leucine amino acid substitution in LOC_Os02g25230 was causative of the observed bc22 phenotype. Additionally, gene expression analysis showed that BC22 had higher expression levels in the culms, leaves, and spikelets compared to the roots. Taken together, our findings indicate that BC22 is a pleiotropic gene, and the influence of BC22 on brittleness may be associated with cell wall biosynthesis in rice culm.

Extraction and characterisation of kudzu root residue lignin based on deep eutectic solvents.

Lignin has great potential as the most abundant renewable phenolic polymer. Studies have shown that lignin structure varies depending on different sources and different extraction methods. However, there are few studies on lignin in kudzu root residue. The aim of the study was to explore optimal extraction conditions of Pueraria lobata residue lignin (PLL) with deep eutectic solvents (DESs) and characterise the structure and morphology of PLL. Firstly, the chemical composition of kudzu root residue was determined by the Van-soest method. Then, betaine was used as hydrogen bond acceptor (HBA), nine kinds of common acids and alcohol were selected as hydrogen bond donor (HBD) to synthesise a DES to extract lignin from kudzu root residue. The influence of conditions on the extraction of PLL was explored by a betaine-based DES according to a single-factor experiment, and then the best process of PLL extraction was determined by an orthogonal experiment. Finally, the morphology and structure of PLL were analysed by scanning electron microscope (SEM), thermogravimetric analysis (TGA), gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), and NMR. Cellulose, hemicellulose, lignin, and ash content in kudzu root residue were 41.13%, 16.39%, 25.03%, and 0.41%, respectively. When the DES consisted of betaine and formic acid, the solid-liquid ratio was 1:45, the extraction time was 5.5 h at 160°C, the extraction yield of lignin was 89.29%, and the purity was 83.01%. PLL was composed of interconnected spherical particles with good thermal stability and narrow polydispersity index (PDI) distribution. FTIR and 2D-heteronuclear singular quantum correlation (HSQC) NMR illustrated that PLL was a typical G-type and S-type lignin. This study would fill the gap of research on lignin in kudzu root residue and provide a theoretical reference for the utilisation of lignin in kudzu roots as well as a new thinking for the recycling of kudzu root resources.

The pretreatment and enzymatic hydrolysis behaviors of lignocellulosic biomass (oak and larch) based on structural changes in its lignin-carbohydrate complex

This study investigated the structural changes in oak and larch lignin-carbohydrate complexes (LCCs) during hydrothermal treatment and enzymatic hydrolysis. Hydrothermal treatment caused hemicellulose degradation (degradation rate at 170 ℃: larch 19.40%; oak, 22.26%). The LCC1 (glucan-lignin) fraction was the highest in the raw material of both biomasses. The LCC3 (xylan-lignin) and LCC2 (glucomannan-lignin) fractions were high in oak and larch, respectively; these fractions decreased as the hydrothermal treatment temperature increased (owing to hemicellulose degradation). Both biomasses had phenyl glycoside, benzyl ether (BE), and γ-ester (Est) linkages. The BE and Est linkages decreased as the hydrothermal treatment temperature increased; the Est linkages decrease was more significantly in oak than in larch. The efficiency of enzymatic hydrolysis was higher in oak than that in larch and increased as the hydrothermal treatment temperature increased. Furthermore, enzyme adsorption on the LCC1 sensor was higher in oak than in larch. The chemical compositions and LCC linkages of the biomass were changed by the hydrothermal treatment, which affected the efficiency of enzymatic hydrolysis. Moreover, the efficiency of enzymatic hydrolysis was higher for oak than for larch because of the difference hemicellulose and cellulose contents and LCC linkages.

Simulation and Optimization of Biohydrogen Production from Biomass Feed via Anaerobic Digestion

AbstractBiomass energy is a renewable energy source that is carbon‐neutral, versatile, and can never go extinct. In the current study, a simulation model of an anaerobic digester with parameters such as pretreatment temperature (PTT), hydraulic retention time (HRT), and feed‐to‐water (F/W) ratio was developed and a design of experiment was created. The results showed that the higher hemicellulose content in sugarcane bagasse (SB) gave a decent H2 yield (13–23 %). The significance sequence was PTT > F/W > HRT. The optimal values were HRT of 15–16 d; F/W of 1.5 (SB), 1.26 [rice straw (RS)], and 0.5 [sawdust (SD)]; and PTT of 63.3 (SB), 68.8 (RS), and 75 °C (SD). The optimal H2 yield was 19.80 (SB), 20.94 (RS), and 21.41 % (SD). Therefore, the present simulation and optimization showed concrete results to raise H2 yield.

Properties and photosynthetic promotion mechanisms of artificial humic acid are feedstock-dependent

AbstractThe artificial humic acids (AHA) approach contributes to achieving the carbon (C) emission peaking and neutrality goal through efficient recycling of waste biomasses and promotion of plant photosynthesis. However, the dependence of their production processes and photosynthetic promotion mechanisms on feedstocks remains unclear. In this study, waste biomasses including camphor leaves (CL), corn stalks (CS), peanut shells (PS), and mixed cyanobacteria (MC) have been respectively converted into artificial humic acids through an environmentally friendly hydrothermal humification approach. The dynamic humification process of different feedstocks and the composition, structural properties, and electron transfer capacity of AHA products were determined. Moreover, the different AHA products were applied to corn to explore their respective photosynthetic promotion mechanisms. High relative contents of lignin and C/N in feedstocks are not conducive to the formation of photodegradable substances and the redox property in AHA. The application of AHA increased the net photosynthetic rate and biomass C of corn by 70–118% and 22–39%, respectively. The AHA produced from higher H/C (0.19) and hemicellulose content (17.09%) in feedstocks (e.g., MC) increased corn photosynthesis by improving light energy capture and conversion efficiency in the PSII process. In contrast, the AHA produced from a higher content of lignin (19.81%) and C/N (7.67) in feedstocks (e.g., CS) increased corn photosynthesis by providing functional enzymes (proteins) and nutrients for leaves. This work provides new insights into the utilization of renewable resources, and the artificial humic acids approach sheds light on environmental sustainability by constructing a closed loop of C in environments. Graphical Abstract

PtoMYB031, the R2R3 MYB transcription factor involved in secondary cell wall biosynthesis in poplar.

The biosynthesis of the secondary cell wall (SCW) is orchestrated by an intricate hierarchical transcriptional regulatory network. This network is initiated by first-layer master switches, SCW-NAC transcription factors, which in turn activate the second-layer master switches MYBs. These switches play a crucial role in regulating xylem specification and differentiation during SCW formation. However, the roles of most MYBs in woody plants are yet to be fully understood. In this study, we identified and isolated the R2R3-MYB transcription factor, PtoMYB031, from Populus tomentosa. We explored its expression, mainly in xylem tissues, and its role as a transcriptional repressor in the nucleus. We used overexpression and RNA interference techniques in poplar, along with Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays, to analyze the regulatory effects of PtoMYB031. Overexpression of PtoMYB031 in poplar significantly reduced lignin, cellulose, and hemicellulose content, and inhibited vascular development in stems, resulting in decreased SCW thickness in xylem tissues. Gene expression analysis showed that structural genes involved in SCW biosynthesis were downregulated in PtoMYB031-OE lines. Conversely, RNA interference of PtoMYB031 increased these compounds. Additionally, PtoMYB031 was found to recruit the repressor PtoZAT11, forming a transcriptional inhibition complex. Our findings provide new insights into how PtoMYB031, through its interaction with PtoZAT11, forms a complex that can suppress the expression of key regulatory genes, PtoWND1A and PtoWND2B, in SCW biosynthesis. This study enhances our understanding of the transcriptional regulation involved in SCW formation in poplar, highlighting the significant role of PtoMYB031.

Production of high-quality dissolving pulp from eucalyptus wood chips using deep eutectic solvent and elemental chlorine-free bleaching

Deep eutectic solvent (DES) provides promising alternatives to conventional pulping and cellulose purification with significantly lower energy consumption and impacts on the environment. In this work, choline chloride – lactic acid (ChCl-LA DES) pulping of eucalyptus wood chips combined with several ECF bleaching sequences was investigated to produce high-grade dissolving pulps. Initially, the dependency of DES pulping yield and delignification efficiency on the moisture content (MC) of used wood chips was evaluated. The results exhibited the crucial influence of the MC of wood chips on the delignification efficiency of DES pulping. DES pulping under optimized conditions resulted in an unbleached pulp with kappa number of 42, relatively high screened yield 48.1% and viscosity 796 cm3/g, as well as very low hemicellulose content, typically less than 3.8%. Further purification of the obtained pulp using D-Ep-D and OO-D-Ep-D bleaching sequences produces several dissolving pulps characterized by a high viscosity 695 cm3/g and brightness 89.5% ISO, indicating low degradation of cellulose during DES pulping. DES pulping exhibited considerable potential to remove the hemicelluloses from wood chips and produce high-quality dissolving pulps. This could be attained through shorter pulping operations conducted at a lower temperature and a higher screened yield compared to current dissolving pulp production operations.

Syngas-Enriched hydrogen production via catalytic gasification of water hyacinth using renewable palm kernel shell hydrochar

Syngas produced from biomass gasification has emerged as a highly promising substitute for conventional fossil fuel, catering to various industrial applications while ensuring minimal greenhouse gas emissions. Water hyacinth (WH) has been a major concern due to its invasive nature and uncontrollable growth which impedes aquatic growth and urban management. Fortunately, WH is a potential biomass feedstock due to the comparable cellulose and hemicellulose contents alongside high carbon content and high calorific value which reflects good biofuel properties. Therefore, this study aims to investigate the conversion of WH biomass via catalytic air gasification for syngas-enriched hydrogen production using palm kernel shell hydrochar (PKSH). A parametric study was conducted in a lab-scale fixed-bed downdraft gasifier based on the response surface methodology coupled with Box-Behnken design (RSM-BBD). The combined interaction effects of the influencing parameters investigated are temperature (600–800 °C), biomass particle size (2–6 mm), catalyst loading (0–10 wt%), and air flow rate (1–3 L/min). Temperature was revealed to be the primary factor with significant influence on the H2 and CO output. Maximum syngas (30.09 vol%) compositions of 11.14 vol% H2 and 18.95 vol% CO were obtained at 800 °C with a particle size of 6 mm and air flow rate of 2 L/min alongside 5 wt% PKSH catalyst loading.

Growth stress and wood properties of 10-year-old fast-growing teak grown in Gunungkidul, Yogyakarta

Abstract The establishment of fast-growing teak plantations in Indonesia provides opportunities for shorter harvesting periods. However, it also poses challenges on wood utilization due to juvenility and growth stress-related defects. This study investigated growth stress levels and some wood properties of 10-year-old fast-growing teak grown in Gunungkidul Regency, Yogyakarta. The strain gauge method was used to measure longitudinal surface released-strains (LRS), tangential surface released-strains (TRS), and longitudinal internal residual strains (IRS). Wood specimens were also collected near each strain measurement point for the analysis of wood properties. The results showed LRS values ranging from −1243 to 320 με, TRS values ranging from −779 to 382 με, and IRS values ranging from −589 to 786 με. Meanwhile, radial variations in fiber length, modulus of elasticity, and lignin content were observed. Significant correlations were found between IRS values and microfibril angle, fiber length, modulus of elasticity, lignin content, and hemicellulose content, while no significant correlations were observed between LRS and TRS values and wood properties. These findings suggest a moderate level of growth stress. Additionally, the results also indicate that this 10-year-old fast-growing teak is still in the juvenile stage. Therefore, its utilization should be performed with caution.

Synergistic effects of ferulic acid esterase-producing lactic acid bacteria, cellulase and xylanase on the fermentation characteristics, fibre and nitrogen components and microbial community structure of Broussonetia papyrifera during ensiling.

The high fibre content of whole plants of Broussonetia papyrifera limits its efficient utilization. Ferulic acid esterase (FAE), in combination with xylanase, can effectively cleave the lignin-carbohydrate complex, promoting the function of cellulase. However, little is known about the impact of these additives on silage. To effectively utilize natural woody plant resources, FAE-producing Lactiplantibacillus plantarum RO395, xylanase (XY) and cellulase (CE) were used to investigate the dynamic fermentation characteristics, fibre and nitrogen components and microbial community structure during B. papyrifera ensiling. Broussonetia papyrifera was either not treated (CK) or treated with FAE-producing lactic acid bacteria (LP), CE, XY, LP + CE, LP + XY or LP + CE + XY for 3, 7, 15, 30 or 60 days, respectively. In comparison with those in the CK treatment, the L. plantarum and enzyme treatments (LP + CE, LP + XY and LP + XY + CE), especially the LP + XY + CE treatment, significantly increased the lactic acid concentration and decreased the pH and the contents of acid detergent insoluble protein and NH3 -N (P < 0.05). Enzyme addition improved the degradation efficiency of lignocellulose, and a synergistic effect was observed after enzyme treatment in combination with LP; in addition, the lowest acid detergent fibre, neutral detergent fibre, hemicellulose and cellulose contents were detected after the LP + CE + XY treatment (P < 0.05). Moreover, CE, XY and LP additions significantly improved the microbial community structure, increased the relative abundance of Lactiplantibacillus and Firmicutes, and effectively inhibited undesirable bacterial (Enterobacter) growth during ensiling. FAE-producing L. plantarum and the two tested enzymes exhibited synergistic effects on improving the quality of silage, which indicates that this combination can serve as an efficient method for improved B. papyrifera silage utilization. © 2023 Society of Chemical Industry.

OBTAINING LACTIC ACID FROM THE FERMENTATION OF RESIDUAL SUGAR CANE, CORN, AND CASSAVA

In this research, lactic acid (LA) was obtained by fermentation from three agricultural residues: cassava husk(CH), corn forage (CF), and sugarcane bagasse (SB). The content of moisture, ash, protein, fat, hemicellulose, cellulose, and lignin for each residue were determined. Then, two chemical pretreatments were applied to CH, CF, and SB: alkaline with 3 % (v.v-1) NaOH, and acid with 8 % (v.v-1) H2SO4. Total reducing sugars (TRS) were determined through the Miller technique (DNS) to select the pretreatment conditions that offered a higher yield in terms of sugar production. Lactic acid fermentation was carried out for 72 hours at 37°C and the amount of lactic acid obtained was determined through HPLC. The highest concentration of ART in acid (8611.90 mg/L) and alkaline hydrolysis was for BC (5526.87 mg/L), respectively. Agricultural residues are a potential resource for the production of biobased products, which currently use raw materials of fossil origin.

Composts of diverse green wastes improve the soil biological quality, but do not alleviate drought impact on lettuce (Lactuca sativa L.) growth

AbstractIntense soil cultivation and climate change have detrimental effects on soils. Solutions are needed to improve the biological quality and water holding capacity of agricultural soils. A greenhouse experiment was conducted to investigate the interactive effect of compost application and drought stress on a soil/plant system in order to determine the improvement of soil quality and plant growth and the alleviation of drought stress. Lettuce (Lactuca sativa L.) was grown under greenhouse conditions in a sandy soil with sufficient mineral fertilizer application to test the effect of five compost types (three made from municipal garden and park wastes with differing nutrient contents, one from municipal household waste, and one from farm plant residues) applied at 30 Mg ha−1 dry weight, with which we compared soil quality and plant growth to soil without compost application. Treatment pots were irrigated or subjected to drought conditions during the last 14 days of lettuce growth. Assays of potential N mineralization during 28 days, dehydrogenase and β‐glucosidase activities, and a phospholipid fatty acid (PLFA) analysis were performed to assess effects on soil biological quality. Gas exchange, leaf relative water content, biomass, nitrogen accumulation, and root tip growth of lettuce were measured to investigate compost and drought stress effects on lettuce physiology. All composts improved indices of soil biological quality significantly, except for fungal abundance, relative to soil without compost. The greatest increase was obtained from farm compost, which significantly increased potential nitrogen (N) mineralization and soil enzyme activities of β‐glucosidase and dehydrogenase by factors of 4, 2, and 43, respectively. Furthermore, soil with farm compost generally showed a higher abundance of soil microbial organisms compared with soil without compost, which could be related to its high cellulose and hemicellulose contents. The lowest abundance of microbial organisms was generally found in soil with garden and park waste compost with a medium nutrient content, which could be related to its low organic matter content. The beneficial effect of compost on soil biological quality did not lead to improved lettuce growth, which suggests that soil biological quality (ameliorated by compost application) is not important for a fast‐growing crop, such as lettuce, that is sufficiently fertilized. Drought stress reduced aboveground lettuce biomass, root tip growth, and the abundance of most soil microbial groups significantly, but compost in soil did not alleviate these negative effects. In conclusion, the farm compost made from grass–clover, straw, and vegetable residues is superior to garden and park waste and household waste composts in terms of beneficial effects on soil biological quality. Compost clearly improved soil biological quality, but did not influence lettuce's response to drought stress. The knowledge gained in this study is useful for producing tailor‐made compost with desired effects of improved soil biological quality.