Utilization Of Organic Matter Research Articles

Spatiotemporal Metabolic Network Models Reveal Complex Autotroph-Heterotroph Biofilm Interactions Governed by Photon Incidences

Autotroph-heterotroph interactions are ubiquitous in natural environment and play a key role in controlling various essential ecosystem functions, such as production and utilization of organic matter, cycling of nitrogen, sulfur, and other chemical elements. Understanding how these biofilm metabolic interactions are constrained in space and time remains challenging because fully predictive models designed for this purpose are currently limited. Toward filling this gap, here we developed community metabolic network models for two autotroph-heterotroph biofilm consortia (termed UCC-A and UCC-O), which share a suite of common heterotrophic members but have a single distinct photoautotrophic cyanobacterium (Phormidesmis priestleyi str. ANA and Phormidium sp. OSCR) that provides organic carbon and nitrogen sources to support the growth of heterotrophic partners. After determining model parameters by data fitting using the spatiotemporal distributions of microbial abundances, we comparatively analyzed the resulting biofilm models to examine any fundamental differences in microbial interactions between the two consortia under the variation of key environmental variables: CO2 and photon levels. The UCC-A model predicted generally expected responses, i.e., the autotroph population increased in response to elevated levels of CO2 and photon, followed by increase in the heterotroph population. In contrast, the UCC-O model showed somewhat complicated dynamics, e.g., higher photon incidence rates resulted in the increase in autotroph population but decrease in heterotroph population due to the lowered provision of glucose from the autotroph. A further analysis showed that species coexistence was governed by the photon incidences rather than the carbon availability for UCC-O, which was the opposite for UCC-A.

Molecular characteristics of organic matter obtained from biochar by carbon disulfide/acetone synergistic extraction

Environmental context Novel insight into BEOMcc is provided by fractionation and FTICR MS. Sub-fractions of biochar were extracted due to the chemical properties of the organic solvents. BEOMcc has a carbon fixation effect, and so is likely beneficial to the growth of plants and microorganisms. Rationale Since carbon disulfide (CS2) has a strong penetrating ability and acetone (CH3COCH3) can dissolve tiny biochar particles, a mixture of these compounds may efficiently extract organic matter from biochar. The extraction efficacy and structural features of a mixture of CH3COCH3 and CS2 (1:1) were tested in this study. Π–Π interactions between CS2 and CH3COCH3 increase the solubility of organic matter in the extraction process. Methodology We used a mixture of CH3COCH3 and CS2 (1:1) to extract organic matter from soybean straw biochar (BEOMcc) and applied Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) for analysis. Results We found that CS2/CH3COCH3 tended to extract refractory substances, and the resulting extract contained a higher number of heteroatoms than the CS2-extractable fraction (1.34 times). Discussion The H/C ratio of BEOMcc is lower than that of CS2- and CH3COCH3-extractable components. The aromatic component of BEOMcc accounts for 52.47%, which is higher than the contribution to CS2-extractable organic matter of approximately 49.9%. The polycyclic aromatic hydrocarbon component of BEOMcc is beneficial to improving soil stability. The organic matter fraction of BEOMcc has a lower H/C ratio. The C/N ratio of BEOMcc is lower than that of the CS2- and CH3COCH3-extractable components. This result reveals that BEOMcc may provide a significant environmental benefit. The polarity of BEOMcc is between that of CS2- and CH3COCH3-extractable components. Implications for future research In this study, the composition of BEOMcc was assessed at the molecular level, and the extraction method was continuously improved to provide more extraction options for the study of biochar–pollutant interactions. This method can be used to extract organic matter that is difficult to extract by conventional methods, which is more closely bound to the biochar framework. It can provide a technical basis for the in‐depth characterisation and utilisation of biochar organic matter.

Isolation and characterization of Lignin-derived monomer degraders under acidic conditions from tropical peatland.

Tropical peatlands account for one of the largest carbon stores in the form of organic matter due to the accumulation of plant litter and waterlogged conditions. Recent anthropogenic disturbances, such as forest fires, agricultural conversion and drainage, in tropical peatlands have caused a vast amount of carbon to be released into the atmosphere, and microbial activities are impacted by these changes. A recent study showed that many phenol- and lignin-degrading bacteria prefer alkaline and neutral pH conditions, while tropical peatland conditions are acidic, possibly changing the mechanisms of the utilization of organic matter from peat soil. The purpose of this study was to isolate and characterize phenolic compound-degrading bacteria from tropical peatlands under acidic conditions due to the lack of information on how the biological processes of microorganisms occur in this unique habitat. Two isolates show the capability to utilize phenolic aldehydes based on building blocks of lignin that are abundant in tropical peatlands, including hydroxyphenyl, guaiacyl and syringyl units. The identification of these isolates by 16S rRNA gene sequence shows that strain S38 is similar to Stenotrophomonas sp., while strain S46 is similar to Burkholderia sp. Further characterization of these isolates shows their ability to degrade 4-hydroxybenzaldehyde and vanillin into phenolic acids within 24 hours of incubation and syringaldehyde within 7 days of incubation. In conclusion, these isolated bacteria show the ability to withstand the acidic environment of tropical peatlands and utilize lignin monomers through unknown metabolic pathways.

Taxon-Specific Shifts in Bacterial and Archaeal Transcription of Dissolved Organic Matter Cycling Genes in a Stratified Fjord

ABSTRACTA considerable fraction of organic matter derived from photosynthesis in the euphotic zone settles into the ocean’s interior and, as it progresses, is degraded by diverse microbial consortia that utilize a suite of extracellular enzymes and membrane transporters. Still, the molecular details that regulate carbon cycling across depths remain little explored. As stratification in fjords has made them attractive models to explore patterns in biological oceanography, we here analyzed bacterial and archaeal transcription in samples from five depth layers in the Gullmar Fjord, Sweden. Transcriptional variation over depth correlated with gradients in chlorophyll a and nutrient concentrations. Differences in transcription between sampling dates (summer and early autumn) were strongly correlated with ammonium concentrations, which potentially was linked with a stronger influence of (micro-)zooplankton grazing in summer. Transcriptional investment in carbohydrate-active enzymes (CAZymes) decreased with depth and shifted toward peptidases, partly a result of elevated CAZyme transcription by Flavobacteriales, Cellvibrionales, and Synechococcales at 2 to 25 m and a dominance of peptidase transcription by Alteromonadales and Rhodobacterales from 50 m down. In particular, CAZymes for chitin, laminarin, and glycogen were important. High levels of transcription of ammonium transporter genes by Thaumarchaeota at depth (up to 18% of total transcription), along with the genes for ammonia oxidation and CO2 fixation, indicated that chemolithoautotrophy contributed to the carbon flux in the fjord. The taxon-specific expression of functional genes for processing of the marine pool of dissolved organic matter and inorganic nutrients across depths emphasizes the importance of different microbial foraging mechanisms over spatiotemporal scales for shaping biogeochemical cycles.IMPORTANCE It is generally recognized that stratification in the ocean strongly influences both the community composition and the distribution of ecological functions of microbial communities, which in turn are expected to shape the biogeochemical cycling of essential elements over depth. Here, we used metatranscriptomics analysis to infer molecular detail on the distribution of gene systems central to the utilization of organic matter in a stratified marine system. We thereby uncovered that pronounced shifts in the transcription of genes encoding CAZymes, peptidases, and membrane transporters occurred over depth among key prokaryotic orders. This implies that sequential utilization and transformation of organic matter through the water column is a key feature that ultimately influences the efficiency of the biological carbon pump.

Fungal biomineralization

Fungi are key organisms of the biosphere with major roles in organic-matter decomposition, element cycling, plant pathogenicity, and symbioses in aquatic and terrestrial habitats. The vast majority exhibit a filamentous, branching growth form and are aerobic chemoorganotrophs that derive carbon and energy from organic substances, and are particularly associated with soil, the plant-root zone, and rock surfaces. It is now known that some fungi are lithotrophs, deriving energy from the oxidation of inorganic materials, whereas others are photoheterotrophs, deriving additional energy from light for organic matter utilization when oxygen is limited. This means that fungi are of much wider environmental significance than previously thought and explains their ubiquity in locations previously thought to be inimical to fungal existence, such as the deep subsurface and other anaerobic locations. In addition to such free-living species, fungi associated with photosynthetic partners are also of profound biosphere importance. For example, lichens, which are composed of a symbiotic association between a fungus and a phototrophic alga and/or cyanobacterium, are pioneer colonizers and bioweathering agents of rocks and minerals. Mycorrhizas are symbiotic, plant-root-associated fungi found to colonize the majority of plant genera, where they improve plant nutrition through solubilization of essential metals and phosphate from soil minerals. Biomineralization in the soil can also immobilize toxic metals in the vicinity of plant roots, thereby benefiting plant colonization and facilitating revegetation of contaminated habitats. Wherever fungi are found, transformation of metals and minerals is a key aspect of their activity, with biomineralization an important feature. Fungal biomineralization is an important facet of geomycology - namely the roles of fungi in geochemical and geophysical processes. This article seeks to highlight the concept of biomineralization as applied to fungi, the occurrence and significance of important fungal biominerals in natural and synthetic environments, and the applied potential of fungal biomineralization in nanobiotechnology.

Enhancement of denitrification efficiency using municipal and industrial waste fermentation liquids as external carbon sources

The addition of external carbon source for nitrogen removal from wastewater is an essential step in wastewater treatment. In this study, various external carbon sources from the fermentation of primary sludge (PS), thickened waste activated sludge (TWAS), food waste (FW), bakery processing & kitchen waste (BP + KW), fat, oil, & grease (FOG), and whey powder (WP) were successfully employed for wastewater denitrification. Methanol and acetate were also used as controls due to their common use as external carbon sources for wastewater denitrification. The denitrification performance and kinetics such as the specific denitrification rate (SDNR), denitrification potential (PDN), and the biomass yield were studied at a constant TVFA as COD/N ratio of 5 for all substrates. Complete denitrification was achieved with a NO3−-N removal efficiency of 98–99%, and no NO2− accumulation was observed at the end of the experiments for all substrates. The results revealed that the liquid fermentation filtrates exhibited higher SDNRs than methanol and acetate. This indicates the high organic matter utilization efficiency and better denitrification ability of fermentation filtrates over conventional carbon sources. WP exhibited the highest SDNR of 17.6 mg NOx − N/g VSS/h, which is approximately four times that of methanol (4.6 mg NOx − N/g VSS/h). The other carbon sources had SDNRs two to three times higher than that of methanol. However, the fermentation filtrates exhibited higher biomass yields of 0.26–0.37 mg VSS/mg COD compared to methanol of 0.21 mg VSS/mg COD, which could lead to higher sludge handling costs. Moreover, methanol exhibited higher PDN of 0.25 g N/g COD compared to all the fermentation filtrates.

Lipid biomarkers, stable C and N isotope ratios coupled with multivariate statistics as sources indicators in coastal sediments of Brunei Bay, Southern South China Sea

The surface distribution of lipid biomarkers, elemental and isotopic compositions (δ13C and δ15N, C/N) were investigated from coastal sediments of Brunei Bay, in order to understand the sources and biogeochemical processes of the organic matter. Fatty acid biomarkers from terrestrial higher plants (e.g., long-chain fatty acids>20), phytoplankton (e.g., 20:5n-3 and 22:6n-3) and microbial activity (e.g., iso-, anteiso fatty acids, 10Me-16:0) were identified. The ratios of carbon and nitrogen isotopes (δ13C, δ15N) and C/N had values ranging from –30.62 to –27.43‰, 1.70 to 3.57‰, and 4.07 to 15.62 respectively, suggesting the prevailed inputs of terrestrially-derived organic matter sources with typical characterization of mangrove estuaries. Principal component analysis separated lipids of autochthonous aquatic production as the major source, followed by allochthonous terrestrial derived input. The presence of bacterial derived lipids and short chain lipids with low and C/N ratios suggest the preferential utilization and decomposition of organic matter by microbial activity. An enrichment of the δ15N ratios could be due to marine cage culture activities and surface runoff from cultivated areas via fluvial transport.

Temperature-induced changes in biofilm organic matter utilization in arctic streams (Disko Island, Greenland)

Temperature-induced changes in biofilm organic matter utilization in arctic streams (Disko Island, Greenland)

Diversity and distribution of viruses inhabiting the deepest ocean on Earth.

As the most abundant biological entities on the planet, viruses significantly influence the overall functioning of marine ecosystems. The abundance, distribution, and biodiversity of viral communities in the upper ocean have been relatively well studied, but our understanding of viruses in the hadal biosphere remains poor. Here, we established the oceanic trench viral genome dataset (OTVGD) by analysing 19 microbial metagenomes derived from seawater and sediment samples of the Mariana, Yap, and Kermadec Trenches. The trench viral communities harbored remarkably high novelty, and they were predicted to infect ecologically important microbial clades, including Thaumarchaeota and Oleibacter. Significant inter-trench and intra-trench exchange of viral communities was proposed. Moreover, viral communities in different habitats (seawater/sediment and depth-stratified ocean zones) exhibited distinct niche-dependent distribution patterns and genomic properties. Notably, microbes and viruses in the hadopelagic seawater seemed to preferably adopt lysogenic lifestyles compared to those in the upper ocean. Furthermore, niche-specific auxiliary metabolic genes were identified in the hadal viral genomes, and a novel viral D-amino acid oxidase was functionally and phylogenetically characterized, suggesting the contribution of these genes in the utilization of refractory organic matter. Together, these findings highlight the genomic novelty, dynamic movement, and environment-driven diversification of viral communities in oceanic trenches, and suggest that viruses may influence the hadal ecosystem by reprogramming the metabolism of their hosts and modulating the community of keystone microbes.

The effect of tillage management on microbial functions in a maize crop at different slope positions

Determining whether agricultural soils act as sinks or sources of greenhouse gases (GHGs) requires the quantification of variations in the pools and fluxes of soil organic carbon (SOC) and nutrients, e.g. nitrogen (N), as well as the associated soil microbial responses. In this study, soil was collected from experimental plots of maize (Zea mays) under conventional, minimum or strip tillage treatments established in a sloping field (~10%) of loamy soil in SW England, UK, where maize had been cultivated conventionally for 12 years. Topsoil (0–10 cm) cores were collected from the top, mid, bottom and foot slope positions to investigate soil C, N and microbial properties. The impact of conventional management on potential GHG emissions was assessed by incubating soils collected from the top, mid and bottom slope positions from the conventional treatment. Contents of SOC and total N were greatest at the top slope position and soil mineral N (NO3−-N and NH4+-N) concentrations were greater at the bottom and foot slope positions in all treatments. Biomarker phospholipid fatty acids (PLFA) for Gram positive bacteria and fungi were relatively 13C-enriched at each slope position regardless of treatment, indicating preferential utilization of organic matter from maize (C4) rather than SOC (C3). Around 70% of carbon incorporated into total PLFA was derived from C3-SOC at the slope foot, indicating that more SOC older than 12 years was being mineralized at the depositional position. Effluxes of N2O and CO2, and total GHG emission were greatest from the incubated soils sampled from the bottom slope position, suggesting that conditions in depositional positions of regularly ploughed sloping arable fields may have increased the potential for mineralization and denitrification. We conclude that the C sink potential of the depositional positions of slopes may be diminished by coincidental GHG emissions.

Metaproteomics Reveals Similar Vertical Distribution of Microbial Transport Proteins in Particulate Organic Matter Throughout the Water Column in the Northwest Pacific Ocean.

Solubilized particulate organic matter (POM) rather than dissolved organic matter (DOM) has been speculated to be the major carbon and energy sources for heterotrophic prokaryotes in the ocean. However, the direct evidence is still lack. Here we characterized microbial transport proteins of POM collected from both euphotic (75 m, deep chlorophyll maximum DCM, and 100 m) and upper-twilight (200 m and 500 m) zones in three contrasting environments in the northwest Pacific Ocean using a metaproteomic approach. The proportion of transport proteins was relatively high at the bottom of the euphotic zone (200 m), indicating that this layer was the most active area of microbe-driven POM remineralization in the water column. In the upper-twilight zone, the predicted substrates of the identified transporters indicated that amino acids, carbohydrates, taurine, inorganic nutrients, urea, biopolymers, and cobalamin were essential substrates for the microbial community. SAR11, Rhodobacterales, Alteromonadales, and Enterobacteriales were the key contributors with the highest expression of transporters. Interestingly, both the taxonomy and function of the microbial communities varied among water layers and sites with different environments; however, the distribution of transporter types and their relevant organic substrates were similar among samples, suggesting that microbial communities took up similar compounds and were functionally redundant in organic matter utilization throughout the water column. The similar vertical distribution of transport proteins from the euphotic zone to the upper twilight zone among the contrasting environments indicated that solubilized POM rather than DOM was the preferable carbon and energy sources for the microbial communities.

The metabolic process of aerobic granular sludge treating piggery wastewater: Microbial community, denitrification genes and mathematical model calculation

Piggery wastewater with high concentration of carbon and nitrogen could be effectively treated by aerobic granular sludge (AGS). However, the underlying mechanisms responsible for simultaneous nitrogen and carbon removal have not been well revealed. Here we conducted a combined analysis of microbial community, denitrification genes and mathematical model calculation to illuminate the metabolic process of this AGS. The relative abundances of the dominant microorganisms were Comamonadaceae (accounting for 24.79%, including Comamonadaceae-un, Ideonella, Comamonas and Variovorax), Saccharibacteria-un (6.07%), Ideonella (5.51%), Luteimonas (4.81%), Bacteroidales (4.09%), Niabella (3.95%), Fillimonas (3.53%), Thauera (3.51%) and Pseudoxanthomonas (3.44%). The dominant microorganisms in the AGS mainly had the potentials of heterotrophic nitrification, aerobic denitrification, organic macromolecule degradation, organics storage and granule stability maintaining. Interestingly, only 0.145% of the communities were found as autotrophic nitrifiers. Moreover, the quantitative analysis of denitrification genes showed the abundance of napA gene was significantly higher than that of narG gene, suggesting that aerobic and anoxic denitrification process coexisted in the AGS, and the former was dominant. Furthermore, the calculations based on mathematical model were used to deduce the nitrification, denitrification and organic matter utilization process in one running cycle of the AGS. The results also indicated that the rapid organic substrates storage in the feast phase might resist the impact of high strength wastewater, and provide carbon and energy sources in the famine phase. Together, our study elucidated the nitrogen and carbon removal process of the AGS treating piggery wastewater with high concentrations.

Direct membrane filtration (DMF) for recovery of organic matter in municipal wastewater using small amounts of chemicals and energy

The recovery and utilization of organic matter in municipal wastewater are essential for the establishment of a sustainable society, such that these factors have drawn significant recent attention. The up-concentration of organic matter via direct membrane filtration (DMF), followed by anaerobic digestion, is advantageous over the treatment of the entire wastewater by an anaerobic process, such as an anaerobic membrane bioreactor (AnMBR). However, the occurrence of severe membrane fouling in the DMF is a problem. In this study, DMF was carried out at an existing wastewater treatment plant to attempt long-term operation. A combination of vibration of membrane modules, short-term aeration, and chemically enhanced backwash (CEB), with multiple chemicals (i.e., the alternative use of citric acid and NaClO), was found to be effective for the mitigation of membrane fouling in DMF. Furthermore, switching the feed from influents to effluents in the primary sedimentation basin significantly mitigated membrane fouling. In this study, in which microfiltration membrane, with a nominal pore size of 0.1 μm, was used, ∼75% of the organic matter in raw wastewater was recovered, with the volumetric concentration of wastewater by 50- or 150-fold. Organic matter recovered by DMF had significantly higher potentials for biogas production than the excess sludge generated from the same wastewater treatment plant. An analysis of the energy balance (i.e., the energy used for DMF and recovered by DMF) suggests that the proposed DMF can produce a net-positive amount of electricity of ∼0.3 kWh from 1 m3 of raw wastewater with a typical strength (chemical oxygen demand of 500 mg/L).

Effect of inclusion of micronized camelina, sunflower, and flax seeds in the broiler chicken diet on performance productivity, nutrient utilization, and intestinal microbial populations

The aim of the study was to evaluate the effect of inclusion of micronized full-fat camelina, flax, or sunflower seeds in the diet for broiler chickens on the performance productivity, nutrient utilization, and composition of intestinal microbial populations and to assess the possibility of modification of the resistance of isolated bacteria to chemotherapeutic agents with different mechanisms of action. The use of micronized oilseeds improved the broiler chicken body weight (P = 0.035) and the FCR value (P = 0.045) in the final rearing stage by enhancement of the utilization of total protein and organic matter. Lactobacillus-Enterococcus spp., Bifidobacterium spp., Escherichia coli, and Salmonella spp. were isolated from small intestinal contents, and Enterobacteriaceae taxa were detected in the cecum and cloaca of the broiler chickens. The addition of micronized camelina seeds (CAM.IR) contributed to an increase in the Bifidobacterium counts in the small intestine, compared with the control treatment (P < 0.050). Escherichia coli bacteria were not isolated only in the CAM.IR treatment. Nitrofurantoin and chloramphenicol were the most effective agents against the isolates from the cecum and cloaca in all oilseed treatments, whereas streptomycin exhibited the lowest efficacy. In the CAM.IR and micronized sunflower seed (SUN.IR) treatments, there were higher counts of trimethoprim/sulfamethoxazole-resistant Enterobacteriaceae strains than in the control and micronized flax seed (FLA.IR) treatments (P < 0.05). There was a difference between strains isolated from the cecum and cloaca only in the FLA.IR treatment, i.e., increased tetracycline sensitivity was exhibited by strains isolated from the cloaca (13% vs. 50%), also in comparison with the control treatments (P = 0.054). In comparison with the CAM.IR and control treatments, reduced numbers of multi-resistant strains were found in the cloaca isolates from the for FLA.IR and SUN.IR variants. Micronized camelina, flax, and sunflower seeds can be used as part of an effective nutritional strategy focused on optimization of the efficiency of rearing broiler chickens, as they positively modify intestinal microbial populations and increase bacterial sensitivity to the analyzed chemotherapeutic agents.

An anaerobic dynamic membrane bioreactor for enhancing sludge digestion: Impact of solids retention time on digestion efficacy

An anaerobic dynamic membrane bioreactor (AnDMBR), which enabled the decoupling of hydraulic retention time (HRT) and solids retention time (SRT), was used for enhancing sludge digestion, with the associated mechanisms elucidated. With the increase of SRT, the biogas production and sludge reduction rate were both enhanced. The specific biogas production and volatile solids (VS) reduction rate were improved to 0.79 L/g VS and 55.9% under SRT 50 d, respectively. Microbial community analysis revealed that Chloroflexi, which is capable of degrading metabolites and dead cells, was enriched at longer SRT. Further analysis showed that both acetoclastic and hydrogenotrophic methanogenesis contributed to the enhanced biogas production under higher SRT compared to the dominance of acetoclastic methanogenesis under lower SRT. The enhanced utilization of organic matter and acetate at longer SRT further confirmed the mechanisms. The results highlighted the potential of AnDMBR for high-efficient sludge digestion.

Pertumbuhan dan Perkembangan Jamur Tiram Putih (Pleurotus ostreatus) pada Media Ampas Sagu

White oyster mushroom (Pleurotus ostreatus) is currently quite popular and much loved by the public because of its delicious taste, high protein content, and low fat. This study aims to measuring the growth of white oyster mushrooms grown on sago dregs media with the treatment of various supplements, measuring the growth power of oyster mushrooms on sago dregs media with the treatment of various kinds of supplements, and measuring the production and efficiency of white oyster mushrooms on the substrate used. This research method consisted of 12 treatments and was repeated 3 times, so that there were 36 experimental units. Research Results White oyster mushrooms grown on MS2 media composition (20 g + MS 80 ml dry sago pulp) showed a good effect on mycelium growth and harvest rapidly. The highest number of fruit bodies was produced in the A3 treatment (20 g of dry sago pulp + 100 ml of water). The highest body weight of fresh mushroom fruit was in the K3 treatment (20 g dry sago pulp + 100 ml coconut water), KN3 (20 g dry sago pulp + 100 ml KN), KN1 (20 g dry sago pulp + 60 ml KN) , and A3 (20 g of dry sago pulp + 100 ml of water). The efficiency of utilization of sago waste organic matter by white oyster mushrooms was 25.84%.

Ecological relevance of high and low nucleic acid content bacteria in a monsoon influenced tropical estuary: Implications on the β-Glucosidase activity

Heterotrophic bacteria that differ in their nucleic acid content are frequently observed in aquatic environments. However, their relevance and roles in organic matter utilization in monsoon-influenced tropical estuaries have not been addressed. Transparent exopolymer particles (TEP) are one of the carbohydrate rich organic matter forms in aquatic environments, and their breakdown is mostly mediated by a heterotrophic bacterial ectoenzyme, i.e., β – glucosidase (BGase). The present study evaluated the influence of shifts in high nucleic acid content– (HNA) and low nucleic acid content – (LNA) bacteria on the degradation of TEP with emphasis on BGase activity. For this, monthly observations were carried out along the Zuari estuary, India, on the abundance of HNA, LNA bacteria, bacterial production (BP), and BGase activity. The results showed that the contribution of HNA bacteria to total bacterial count was high and positively influenced the BP and BGase activity during the non-monsoon seasons, which represents a well-mixed water column. During this time, HNA also influenced the active utilization of TEP. Whereas, LNA bacteria dominated during the monsoon, wherein the water column is strongly stratified, and showed decoupling with BGase activity, irrespective of the depth. Redundancy and response curve analyses revealed that the interactive effect of monsoon (rainfall) and stratification significantly altered the bacterial activity in this estuary. Besides, the variability in side scatter (SSC), and fluorescence intensity (FL 1) of HNA and LNA bacteria suggest that these two groups play distinct ecological roles in the tropical estuarine systems. Unravelling the links between the different nucleic acid content bacteria and their phylogenetic composition can provide insights into their functional roles in monsoonal estuaries.

Determinants of Compliance to Good Agricultural Practices among Cocoa Farmers in Ondo State, Nigeria

Cocoa is one of Nigeria’s most important agricultural commodities due to its status as a source of foreign exchange earnings. However, low quality and hence low patronage of cocoa beans of Nigeria origin has reduced this fortune in recent years due mainly to non-adherence to Good Agricultural Practices (GAP) among farmers. The study therefore identified the determinants of compliance to GAP among cocoa farmers in Ondo State, Nigeria. A three-stage sampling procedure was used to select 20% (150) of cocoa farmers across randomly sampled cocoa-producing communities in Ondo State. Information was sourced using a well-structured, validated questionnaire. Data were analyzed using frequency counts, mean and Ordinary Least Square (OLS). Majority of farmers had good knowledge of GAP. However, farmers were mostly faced with constraints such as high cost of agrochemicals and labor scarcity. Farmers rated economic benefits of GAP as high; while health and environmental benefits were rated low; with high acceptability of cocoa; utilization of soil organic matter and prevention of respiratory malfunctioning identified as top economic, environmental and health benefits, respectively. Although the general compliance was high across different GAP, practices to which farmers were least compliant were however of relatively high economic, health and environmental implications. Knowledge, perceived health and perceived economic benefits of GAP were important determinants of compliance. The extension unit of the Ondo State Ministry of Agriculture should prioritize sensitization and education of farmers on the economic, health and environmental benefits of GAP of cocoa in order to ensure profitability and sustainability of production.

Stable Isotope Mixing Models Are Biased by the Choice of Sample Preservation and Pre-treatment: Implications for Studies of Aquatic Food Webs

Stable isotope analysis has become one of the most widely used techniques in ecological studies. However, there are still uncertainties about the effects of sample preservation and pre-treatment on the ecological interpretation of stable isotope data and especially on Bayesian stable isotope mixing models. Here, Bayesian mixing models were used to study how three different preservation methods (drying, freezing, formalin) and two pre-treatments (acidification, lipid removal) affect the estimation of the utilized organic matter sources for two benthic invertebrate species (Limecola balthica, Crangon crangon) collected in the Baltic Sea. Furthermore, commonly used mathematical lipid normalization and formalin correction were applied to check if they were able to adjust the model results correctly. Preservation effects were strong on model outcomes for frozen as well as formalin preserved L. balthica samples, but not for C. crangon. Pre-treatment effects varied with species and preservation method and neither lipid normalization nor mathematical formalin correction consistently resulted in the desired model outcomes. Our analysis highlights that particularly small, not significant changes in stable isotope ratios introduced by different preservation and pre-treatments display a so far unrecognized source of error in stable isotope mixing models. We conclude that mathematical correction of benthic invertebrate stable isotopes data should be avoided for Bayesian mixing models and that previously unaddressed effects of sample preservation (especially those arising from preservation by freezing) have potentially biased our understanding of the utilization of organic matter in aquatic food webs.

Comparative optimisation of biohythane production from starch wastewater by one-stage and two-stage anaerobic digestion

Now, energy crisis was the problem in the world. This research was study the biohythane production for renewable energy. The experiment was optimised using starch by one-stage and two-stage anaerobic digestion in batch reactor. For two-stage, the optimal conditions of biohythane production were pH 7.0, thermophilic temperature, C/N ratio 30 for a first step (hydrogen yield 63.65 mL H2/g COD) and pH 7.5, thermophilic temperature, C/N ratio 30 for a second step (methane yield 184.59 mL CH4/g COD). Furthermore, one-stage was achieved at an initial pH 7.5 under thermophilic temperature and C/N ratio 30 (methane yield 206.47 mL CH4/g COD). At optimal conditions, the maximum COD removal of two-stage (73.75%) was higher than that of one-stage (68.70%). Overall bioenergy recovery of two-stage was more generation than that of one-stage, including utilisation of organic matter at the same time.