Utilization Of Organic Substrates Research Articles

Operational characteristics in varied gradients of low carbon-to-nitrogen ratios utilizing a novel integrated bacteria-algae synergistic biofilm reactor for wastewater treatment

Evaluating a novel algal-bacterial biofilm integrated reactor (A-BBR) designed to reduce energy consumption and greenhouse gas emissions, wastewater treatment characteristics were simulated at low carbon-to‑nitrogen ratios. Pollutant removals were investigated under low organic loads at different carbon-to‑nitrogen ratios (ranging from 7.24 to 4.59). COD and NH4+-N removal rates surpassed 90 %, with TN removal exceeding 80 %, demonstrating a notable performance improvement over the fixed-bed biofilm reactor (FBBR). The efficient utilization of organic substrate during denitrification by the bacteria-algae symbiosis system resulted in an increase in nitrogen removal per unit concentration of organic matter. Tracking studies of photosynthetic oxygen production rate versus specific aerobic rate and chlorophyll in the reactor demonstrated that additional aeration was unnecessary during the photoreaction phase, reducing energy losses. The decrease in the carbon-to‑nitrogen ratio was positively correlated with the increase in facultative diatom species within the biofilm. As the carbon-to‑nitrogen ratio had decreased from 7.24 to 4.59, the content of diatoms had increased by over tenfold compared to the initial stage. Furthermore, as the diversity of algae species increased, the difference between the photosynthetic oxygen production rate and the specific aerobic rate had risen from 7.6 to 13.8. This indicated that the algal-bacterial biofilm system with a richer diversity of algae exhibited a higher photosynthetic oxygen production rate compared to the monoalgal system. These results furnish valuable insights for future inquiries into the utilization and underlying mechanisms of bacterial and algal biofilms in the context of water treatment.

Kinetics of microbial cell growth, utilization of organic substrates and methane production in upflow anaerobic filters in two and three separated stages treating sanitary landfill leachates

AbstractThis paper deals with the kinetics of microbial cell growth, utilization of organic substrates and methane production in upflow anaerobic filters in two and three separated stages (UAF‐2SS and UAF‐3SS) treating sanitary landfill leachates, under three temperatures (20, 27, and 34°C), fed with volumetric organic loads (VOLs) for UAF‐2SS (1.8, 2.25, 2.76, 3.45, 3.71, 4.64 kgCOD (chemical oxygen demand)/m3/d) and UAF‐3SS (1.7, 2.25, 2.44, 2.6, 3.15, 3.45, 3.5, 4.57, 4.64, 6.31, 11.61, 14.18, 17.48 kgCOD/m3/d). Kinetic parameters were obtained at temperature (20–34°C), pH (8.8–9.1), each one of three stages within the UAF‐2SS and UAF‐3SS reactors containing methanogenic bacteria (Methanococcus sp., and Methanobacterium sp.) and Clostridium sp.: Maximum substrate utilization rate (rm,s) resulted in 102 mg COD/L/h, maximum microbial cell growth rate (μm) varied 102–103 CFU (colony forming units)/mL/h, methane (CH4) production rate (rm,CH4) tended to vary 100–101 mg CH4/d and the maximum production coefficient (Y) varied 0–102 CFU/mL/h/mgCOD/L/h.

The dispersion of Trichosporon fermentans was controlled by optimizing the shear environment in the reactor to improve the cell sedimentation and separation performance

The morphology of pseudomycelium in Trichosporon fermentans is not conducive to the accumulation of lipids and the recovery of yeast cells by sedimentation. In this study, the computational fluid dynamics method was used to study the effects of shear force on the flow field distribution and on the dimorphism transition and dispersion of yeast cells in a 5 L stirred bioreactor, and to explore the sedimentation performance of yeast cells in different forms. It was shown that under the condition of moderate shear force, such as 3.45 Pa corresponding to a stirring speed of 300 rpm as selected in this experiment, most of the yeast cells in the fermentation broth were spherical or short rod-shaped, and there were almost no pseudohyphal yeasts, which contributed to the good sedimentation performance of the yeast cells. The results showed that the appropriate shear force could effectively inhibit the transformation of yeast cells into pseudohyphae, retain a large number of cells in a single cell shape, enhance cell dispersion and facilitate cell contact, absorption and utilization of organic substrates, as well as increase the lipid accumulation in yeast cells. By controlling the shear force, after 40 h of treatment of RSOW using Trichosporon fermentans, the chemical oxygen demand and oil content removal were approximately 95.81% and 88.09%, respectively, which indicate a significant improvement compared with those before optimizing the shear environment. Therefore, based on shear control of the cell morphology to improve yeast cell dispersion and sedimentation performance, the oily wastewater treatment method established in this study can be used to guide the process design of fermented Trichosporon fermentans for the treatment of RSOW and the resource recycling of yeasts.

Latest Trends in Microbial Biofuels

Biofuel research is presently an area of immense interest due to the enlargement in global energy command by emerging economies and the recent growth in global oil prices. The utilization of organic substrates by a micro organism and its further utilization in the metabolic process gives rise to useful products.

Improving yield and quality of vegetable grown in PAEs-contaminated soils by using novel bioorganic fertilizer

Phthalate acid esters (PAEs) are ubiquitous pollutants in agricultural soils. Application of bioorganic fertilizer (BOF) containing beneficial microbes represents a promising approach to improve the yield and quality of crops grown in contaminated soils. In the present study, a novel multifunctional bioorganic fertilizer N-BOF was developed by using compost of sewage sludge and agricultural waste and inoculating with PAEs-degrading B. megaterium YJB3 and phosphate solubilizing B. megaterium YLYP1. Its feasibility of improving the yield and quality of vegetable grown in PAEs (including DBP and DEHP) contaminated soil was evaluated by pot experiments. The N-BOF could effectively promote plant growth, with biomass increasing by 4–66.9% and 19–110% compared to chemical (CF) and no fertilizer (CK), respectively. The concentrations of DBP and DEHP in shoots of chemically fertilised vegetable ranged 1.23–3.12 mg/kg (dry weight, DW) and 1.63–3.89 mg/kg (DW), respectively. Their concentrations were significantly decreased (p < 0.05) when N-BOF was applied (1%, 2%, 5% amendment), especially at higher application rate ranging 0.11–0.3 mg/kg (DW) and 0.16–0.32 mg/kg (DW), respectively. Meanwhile, vegetable quality attributes were also significantly improved when 2% N-BOF was applied, with increase in the contents of vitamin C, vitamin B1, total protein, and starch, and decrease in the contents of nitrite and nitrate. In this case, the human health risk from consumption of the vegetable grown in PAEs-contaminated soil could be significantly reduced. Thus, our study is expected to provide an efficient way of high-value utilization of organic substrates by producing low-cost but high quality N-BOF. Future studies on the effects of N-BOF in terms of fertilizer regimes on yield and quality of the vegetable are needed, and further field studies for assessing the long-term efficacy and reliability of this promising N-BOF are also warranted.

Microbial carbon use efficiency, biomass turnover, and necromass accumulation in paddy soil depending on fertilization

Microbial anabolism relative to catabolism, reflected by the C use efficiency (CUE), determines the fate of C transformation in soil. Understanding how the microbial CUE and microbial necromass respond to fertilization is crucial for the evaluation of the C sequestration potential in intensively managed paddy soils. We examined the microbial CUE, microbial biomass turnover, and necromass accumulation in rice rhizosphere and bulk soils subjected to long-term (31 years) fertilizations: no fertilizers (control), mineral fertilizers alone (NPK), mineral fertilizers plus rice straw incorporation (NPK-Straw), and mineral fertilizers combined with a low or a high amount of organic manure (NPK-lowM or NPK-highM). The microbial CUE was determined by 18O incorporation into DNA. Microbial necromass accumulation was quantified by the biomarker analysis of amino sugars. Rice straw and manure incorporation reduced the microbial CUE in the rhizosphere soil, whereas the CUE remained constant in the bulk soil. CUE was lower in the rhizosphere soil than in the bulk soil due to nutrients uptake and root exudate release by rice plants, leading to a higher C/nutrient ratio in the rhizosphere. Organic inputs strengthened these rhizosphere processes and could thus weaken the relative potential of C sequestration. The microbial CUE decreased with the increase of the available C/N ratio in the rhizosphere but not in the bulk soil. The microbial CUE mainly depended on the respiration in the bulk soil and on the microbial growth in the rhizosphere soil, indicating the divergent microbial utilization of organic substrates between rhizosphere and bulk soils. In both rhizosphere and bulk soils, organic inputs promoted the microbial biomass growth rate and further increased the amount of microbial necromass by 27–52 % compared with NPK alone, which was highly correlated with the soil organic C pools. Despite enhancing rhizosphere respiration, our findings highlight that rice straw and manure applications increase C sequestration in paddy soils by enhancing the net flux of microbial biomass formation, and consequently promoting necromass accumulation.

Recovery dynamics of prokaryotes and extracellular enzymes during sediment rewetting after desiccation

Intermittent flow of headwaters occurs with increasing frequency in temperate regions over last decades. Here, we assessed the effects of rewetting process on benthic prokaryotic communities from the Breitenbach (Hesse, Germany) for 10 days following experimental drought of different duration and intensity, by measuring the abundance of selected prokaryotic groups and potential extracellular enzyme activities (EEA). Desiccation time and intensity affected the recovery of the microbial community structure and the utilization of organic substrates in sediments, but recovery differed among prokaryotic groups and enzymes. Prokaryotes grew moderately to levels above the initial wet state, whereas Alphaproteobacteria were promoted. The EEA increased rapidly with overshoots within the first days of rewetting indicating high activation after desiccation. The ratios between the EEA changed with the duration of desiccation indicating changes of macromolecular organic matter utilization. The prokaryotic community and its functions were still distinctly different from the initial stream situation, and thus no resilience could be considered after short time (10 days) of recovery from desiccation. We propose that desiccation effects might be enhanced, if desiccation events occur under the effect of changing climate more often, more regularly, and/or for longer time spans.

Cultivation-Independent and Cultivation-Dependent Analysis of Microbes in the Shallow-Sea Hydrothermal System Off Kueishantao Island, Taiwan: Unmasking Heterotrophic Bacterial Diversity and Functional Capacity

Shallow-sea hydrothermal systems experience continuous fluctuations of physicochemical conditions due to seawater influx which generates variable habitats, affecting the phylogenetic composition and metabolic potential of microbial communities. Until recently, studies of submarine hydrothermal communities have focused primarily on chemolithoautotrophic organisms, however, there have been limited studies on heterotrophic bacteria. Here, fluorescence in situ hybridization, high throughput 16S rRNA gene amplicon sequencing, and functional metagenomes were used to assess microbial communities from the shallow-sea hydrothermal system off Kueishantao Island, Taiwan. The results showed that the shallow-sea hydrothermal system harbored not only autotrophic bacteria but abundant heterotrophic bacteria. The potential for marker genes sulfur oxidation and carbon fixation were detected in the metagenome datasets, suggesting a role for sulfur and carbon cycling in the shallow-sea hydrothermal system. Furthermore, the presence of diverse genes that encode transporters, glycoside hydrolases, and peptidase indicates the genetic potential for heterotrophic utilization of organic substrates. A total of 408 cultivable heterotrophic bacteria were isolated, in which the taxonomic families typically associated with oligotrophy, copiotrophy, and phototrophy were frequently found. The cultivation-independent and -dependent analyses performed herein show that Alphaproteobacteria and Gammaproteobacteria represent the dominant heterotrophs in the investigated shallow-sea hydrothermal system. Genomic and physiological characterization of a novel strain P5 obtained in this study, belonging to the genus Rhodovulum within Alphaproteobacteria, provides an example of heterotrophic bacteria with major functional capacity presented in the metagenome datasets. Collectively, in addition to autotrophic bacteria, the shallow-sea hydrothermal system also harbors many heterotrophic bacteria with versatile genetic potential to adapt to the unique environmental conditions.

Effects of Rhizobium Species Living with the Dark Septate Endophytic Fungus Veronaeopsis simplex on Organic Substrate Utilization by the Host.

Bacteria harbored in/on the hyphae of the dark septate endophyte, Veronaeopsis simplex Y34, were identified as a single Rhizobium species by molecular analyses of bacterial 16S rRNA genes, and were successfully isolated from the endophyte. The Rhizobium-cured fungus was prepared thoroughly by an antibiotic treatment, thereby allowing an examination of their effects on organic substrate utilization. Assays with Biolog® FF microplates revealed that the respiration potential for 52.6% of the tested compounds were significantly different between Rhizobium-harboring and -cured fungal hosts, indicating that organic substrate utilization by V. simplex Y34 was significantly influenced by the presence of the associated Rhizobium sp. VsBac-Y9.

Ecological and functional effects of fungal endophytes on wood decomposition

Abstract Despite the central role of saprotrophic fungi in wood decomposition and terrestrial carbon cycling, the diversity and functioning of wood endophytes (i.e. fungi that asymptomatically colonize living plant tissue) on decay remains poorly understood. In a 4‐year field experiment in a boreal forest in the upper midwestern United States, we investigated whether endophytes influenced fungal community structure and subsequent wood decomposition via priority effects. We compared decay of sterilized and non‐sterilized birch (Betula papyrifera) logs using both high‐throughput sequencing and wood physiochemical analyses (i.e. density loss, dilute alkali solubility, ratio of lignin loss relative to density loss). Endophyte presence significantly altered initial fungal species composition during the first 2 years and enhanced mass loss over the experiment's duration. Results suggest that following tree death the immediate utilization of organic substrates by wood endophytes significantly alters establishment patterns of later arriving fungal saprotrophs. Independent of endophyte presence, white rot was the wood decay outcome at all sampling times, despite an initial presence of both brown and white rot fungi. Collectively, these findings demonstrate that wood endophytes can affect early community assembly and subsequent decay rates, although environmental filtering leads to consistent selection for fungi with lignin‐targeted decay strategies. A plain language summary is available for this article.

Denitrification aided by waste beer in anaerobic sequencing batch biofilm reactor (AnSBBR)

The goal of research was to examine waste beer as a source of carbon in an anaerobic sequencing batch biofilm reactor (AnSBBR). It was demonstrated that waste beer enhanced denitrification. Observed biomass yield coefficient (Yobs) was one size of magnitude lower than for suspended-biomass reactors (0.03±0.03mgTSSmgCOD−1). The kinetic parameters (utilization of organic substrate and denitrification rates) were lower during the start-up period (88.8mgO2L−1h−1 and 17.37mgNL−1h−1, respectively) than during stable operation of the reactor (212.4mgO2L−1h−1 and 34.66mgNL−1h−1 after 180 cycles). The metagenomic results showed that the abundance of Alcaligenes decreased from 18.39% to 0.88% (in 180 cycle), whereas the read numbers of Trichococcus increased gradually from 2.93% to 52.26% (in 180 cycle). Trichococcus was the dominant microorganism (52.3%). The low value of Yobs most likely resulted from the ability of Trichococcus to degrade complex organic compounds and extracellular polysaccharide substances (EPS), released from dead cells in deeper layers of the biofilm.

Influences of Black Locust (Robinia pseudoacacia L.) afforestation on soil microbial biomass and activity

Abstract: Black locust is a tree species considered suitable for afforestation in Turkey because of its rapid growth and ability to fix atmospheric nitrogen in disturbed soil ecosystems. Quantitative indicators of soil health and quality can be usefully derived from a data set of soil physical, chemical and microbial characteristics. In this study changes in soil characteristics after afforestation with black locust were assessed by comparing several afforestation sites with control (no vegetation) sites randomly chosen along the roadside in Ulus-Bartin, the western Black Sea region (Turkey). Results showed that some physical and chemical characteristics of the soil (soil bulk density, clay content, soil organic C and total N) were higher at the afforestation sites as compared with the control sites. Similarly, afforestation sites showed higher values for mean soil microbial biomass C (afforestation: 311.97 µg g-1;control: 149.68 µg g-1) and N (afforestation: 43.07 µg g-1; control: 19.21 µg g-1), and basal respiration (afforestation: 0.303 µg CO2-C g-1 h-1; control: 0.167 µg CO2-C g-1 h-1). However, the mean metabolic quotient (qCO2) assessed at the control sites was higher (1.47 mg CO2-C g-1 Cmic h-1) than that observed the afforestation sites (0.96 mg CO2-C g-1 Cmic h-1), likely due to difficulties in the utilization of organic substrates by the microbial community. In addition, the correlation between the qCO2 and Cmic/Corg percentages was negative (r = - 0.586, P < 0.01) in both sites. Our results indicated that afforestation with black locust could be advantageous, not only for soil improvement and regeneration, but also for sustainable land management.

Fungal and bacterial utilization of organic substrates depends on substrate complexity and N availability

There is growing evidence of a direct relationship between microbial community composition and function, which implies that distinct microbial communities vary in their functional properties. The aim of this study was to determine whether differences in initial substrate utilization between distinct microbial communities are due to the activities of certain microbial groups. We performed a short-term experiment with beech forest soils characterized by three different microbial communities (winter and summer community, and a community from a tree-girdling plot). We incubated these soils with different (13) C-labelled substrates with or without inorganic N addition and analyzed microbial substrate utilization by (13) C-phospholipid fatty acid (PLFA) analysis. Our results revealed that the fate of labile C (glucose) was similar in the three microbial communities, despite differences in absolute substrate incorporation between the summer and winter community. The active microbial community involved in degradation of complex C substrates (cellulose, plant cell walls), however, differed between girdling and control plots and was strongly affected by inorganic N addition. Enhanced N availability strongly increased fungal degradation of cellulose and plant cell walls. Our results indicate that fungi, at least in the presence of a high N supply, are the main decomposers of polymeric C substrates.

Acute impact of erythromycin and tetracycline on the kinetics of nitrification and organic carbon removal in mixed microbial culture

The study evaluated acute impact of erythromycin and tetracycline on nitrification and organic carbon removal kinetics in mixed microbial culture. Acclimated biomass was obtained from a fill and draw reactor fed with peptone mixture selected as synthetic substrate and operated at a sludge age of 10 days. Acute inhibition was tested in batch reactors involving a control unit started solely with substrate and the others with additional doses of each antibiotic. Modeling indicated that both steps of nitrification were totally blocked by erythromycin. Tetracycline inhibited and retarded nitrification kinetics at 50 mg/L and stopped nitrite oxidation at 200 mg/L, leading to nitrite accumulation. Both antibiotics also affected organic carbon removal by inducing partial inactivation of the heterotrophic community in the culture, increased substrate storage and accelerated endogenous respiration, with a relatively slight impact on heterotrophic growth. Major inhibitory effect was on process stoichiometry, leading to partial utilization of organic substrate.

Thiosulfate-related microbial communities from four arid soils in the Southwestern United States

Sulfur-deficiency has been observed in arid and semi-arid soils. To explore sulfur cycling in arid soils, four (4) arid soils collected from the Southwestern United States were tested for 12 chemical constituents and moisture content, and soil microbial communities were assayed for the ability to utilize a set of 31 organic substrates using EcoPlates™. Soils were cultured for the presence of sulfur-utilizing bacteria using thiosulfate as the sulfur source. The densities of thiosulfate-utilizing bacterial populations were determined using viable plate counts and differential media. Results showed that the soils contained high amounts of sulfate, calcium and other minerals. Active soil microbial communities utilized 24–31 organic substrates. The density of thiosulfate-utilizing bacterial populations ranged from 105 colony forming units per gram (cfu g−1) to greater than 106 cfu g−1. Regression analyses showed that there were no statistically significant correlations between the density of thiosulfate-reducing bacteria and other tested variables. However, the high density of sulfur-related bacteria and high organic substrate utilization by the microorganisms suggests that these organisms may be important in sulfur and carbon cycling in these soils.

Depth-Related Differences in Organic Substrate Utilization by Major Microbial Groups in Intertidal Marine Sediment

Depth-Related Differences in Organic Substrate Utilization by Major Microbial Groups in Intertidal Marine Sediment

Depth-Related Differences in Organic Substrate Utilization by Major Microbial Groups in Intertidal Marine Sediment

Stable isotope probing of magnetic-bead-captured rRNA (Mag-SIP) indicated clear differences in in situ organic substrate utilization by major microbial groups between the more oxidized (0 to 2 cm) and sulfate-reducing (2 to 5 cm) horizons of marine intertidal sediment. We also showed that cyanobacteria and diatoms may survive by glucose utilization under dark anoxic conditions.

Characteristics of a phylogenetically ambiguous, arsenic-oxidizing Thiomonas sp., Thiomonas arsenitoxydans strain 3AsT sp. nov

A moderately acidophilic, facultative chemoautotrophic, As(III)-oxidizing Thiomonas sp. (strain 3As(T)) was previously shown, on the basis of comparative 16S rRNA gene sequences, to be closely related to both Tm. perometabolis DSM 18570(T) and Tm. intermedia DSM 18155(T). While it had shared many physiological traits with Tm. intermedia (T), a mean DNA-DNA hybridization value (DDHV) of 47.2% confirmed that strain 3As(T) was not a strain of Tm. intermedia, though the situation with regard to Tm. perometabolis (DDHV previously determined as 72%) was more ambiguous. A comparative physiological and chemotaxonomic study of strain 3As(T) and Tm. perometabolis (T) was therefore carried out, together with multilocus sequence analysis (MLSA) of all three bacteria. Differences in fatty acid profiles and utilization of organic substrates supported the view that strain 3As(T) and Tm. perometabolis are distinct species, while MLSA showed a closer relationship between strain 3As(T) and Tm. intermedia (T) than between strain 3As(T) and Tm. perometabolis (T). These apparent contradictory conclusions were explained by differences in genome of these three bacteria, which are known to be highly flexible in Thiomonas spp. A novel species designation Thiomonas arsenitoxydans is proposed for strain 3As(T) (DSM 22701(T), CIP 110005(T)), which is nominated as the type strain of this species.

Azospirillum thiophilum sp. nov., a diazotrophic bacterium isolated from a sulfide spring

A novel nitrogen-fixing strain, designated BV-S(T), was isolated from a sulfur bacterial mat collected from a sulfide spring of the Stavropol Krai, North Caucasus, Russia. Strain BV-S(T) grew optimally at pH 7.5 and 37°C. According to the results of phylogenetic analysis, strain BV-S(T) belonged to the genus Azospirillum within the family Rhodospirillaceae of the class Alphaproteobacteria. Within the genus Azospirillum, strain BV-S(T) was most closely related to Azospirillum doebereinerae GSF71(T), A. picis IMMIB TAR-3(T) and A. lipoferum ATCC 29707(T) (97.7, 97.7 and 97.4 % 16S rRNA gene sequence similarity, respectively). DNA-DNA relatedness between strain BV-S(T) and A. doebereinerae DSM 13131(T), A. picis DSM 19922(T) and A. lipoferum ATCC 29707(T) was 38, 55 and 42 %, respectively. Similarities between nifH sequences of strain BV-S(T) and members of the genus Azospirillum ranged from 94.5 to 96.8 %. Chemotaxonomic characteristics (quinone Q-10, major fatty acid C(18 : 1)ω7c and G+C content 67&emsp14;mol%) were similar to those of members of the genus Azospirillum. In contrast to known Azospirillum species, strain BV-S(T) was capable of mixotrophic growth under microaerobic conditions with simultaneous utilization of organic substrates and thiosulfate as electron donors for energy conservation. Oxidation of sulfide was accompanied by deposits of sulfur globules within the cells. Based on these observations, strain BV-S(T) is considered as a representative of a novel species of the genus Azospirillum, for which the name Azospirillum thiophilum sp. nov. is proposed. The type strain is BV-S(T) (=DSM 21654(T) =VKM B-2513(T)).

Microbiological parameters as indicators of soil organic carbon dynamics in relation to different land use management

Labile C fractions: microbial biomass C (MBC), K2SO4 extractable C ( $$ {\text{C}}_{{{\text{K}}_{ 2} {\text{SO}}_{ 4} }} $$ ) and the cumulated mineralized C in 21 days incubation at 28°C (C–CO2(21d)), were compared as land use indicators in a calcareous soil under three different management systems: native Querqus ilex forest (under and outside tree cover), a Pinus halepensis plantation, and cropped land (with cereals). Microbial biomass and activity were found to be low and coincided with high carbonate contents. As indicators of land use, $$ {\text{C}}_{{{\text{K}}_{ 2} {\text{SO}}_{ 4} }} $$ and C–CO2(21d) showed the same sensitivity as MBC. C–CO2 emissions were measured in an incubation experiment in order to study C mineralization kinetics. The data for cumulative amounts of C–CO2 released showed a good fit (R 2 > 0.94) to the first-order kinetic model C m = C o(1 − e−kt ). The kinetic parameters C o and C o k were affected by land use and especially by tree cover. Principal components analysis was applied to the data and the relationship among microbial metabolic quotient (qCO2), labile C pools, and MBC revealed a decrease in efficiency of organic substrate utilization with an increase in availability and lability of the organic matter.