해안 도시에서 수집된 음식물류폐기물의 성상 및 생화학적 메탄 가스 발생 잠재력 연중 변화 분석

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Biokinetics of Protein Degrading Clostridium cadaveris and Clostridium sporogenes in Batch and Continuous Mode of Operations

A quantitative real-time polymerase chain reaction (QPCR) was applied to estimate biokinetic coefficients of Clostridium cadaveris and Clostridium sporogenes, which utilize protein as carbon source. Experimental data on changes in peptone concentration and 16S rRNA gene copy numbers of C. cadaveris and C. sporogenes were fitted to model. The fourth-order Runge-Kutta approximation with non-linear least squares analysis was employed to solve the ordinary differential equations to estimate biokinetic coefficients. The maximum specific growth rate (mu(max)), half-saturation concentration (K-s), growth yield and decay coefficient (K-d) of C. cadaveris and C.sporogenes were 0.73 +/- 0.05 and 1.35 +/- 0.32 h(-1), 6.07 +/- 1.52 and 5.67 +/- 1.53 g/l, 2.25 +/- 0.75 x 10(19) and 7.92 +/- 3.71 x10(9) coples/g, 0.002 +/- 0.003 and 0.002 +/- 0.001 h(-1), respectively. The theoretical specific growth rate of C. sporogenes always exceeded that of C. cadaveris at peptone concentration higher than 3.62 g/l. When the influent peptone concentration was 5.0 g/l, the concentration of C.cadaveris gradually decreased to the steady value of 2.9 x 10(10) coples/ml at 4 h Hydraulic retention time (HRT), which indicates a 67.1% reduction of the initial population, but the wash out occurred at HRTs of 1.9 and 3.2 h. The 16S rRNA gene copy numbers of C. sporogenes gradually decreased to steady values ranging from 1.1 x 10(10) to 2.9 x 10(10) coples/ml. C. sporogenes species was predicted to wash out at an HRT of 1.6 h.11Nsciescopuskc

Effect of different microbial seeds on batch anaerobic digestion of fish waste

Initial microbial compositions would be the precursor for the efficient anaerobic digestion (AD) of fish waste (FW). A mesophilic batch test was conducted using four seeds collected from different digesters treating various combinations of substrates to investigate their effects on FW degradation. Key microbial groups were identified by 16s rRNA gene-based metagenomics analysis. Among four, the seed from the digester co-digesting livestock manure, food waste, and food wastewater showed the best performance and obtained the highest methane yield (350.5 ± 5.2 mL/gVSadded) and lowest lag phase (0.6 ± 0.1 d). Proteiniphilum, Aminobacterium, dgA-11 gut group, and Syntrophomonas were dominant bacterial genera identified in FW degradation. Methanosaeta was the dominant methanogen in the best performing seed and microbial network analysis revealed its contribution to achieving the highest CH4 yield. Obtained results could be useful in selecting microbial seed sources to avoid system imbalance in full-scale digesters that treat FW.11Nsciescopu

Anaerobic methanation of acetate using different initial methanogenic diversities

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Long-term enrichment of anaerobic propionate-oxidizing consortia: Syntrophic culture development and growth optimization

Propionate is a quantitatively important methanogenic intermediate in anaerobic digesters and only limited number of microbes can utilize it under syntrophic association with methanogens. The syntrophic propionate oxidizing bacterias are known to be slow growers due to the low energy yield. Thus, propionate get accumulated frequently in anaerobic digesters and it negatively affect digester performance. In this study, propionate degrading consortia from four different seeding sources were enriched in sequential bath mode in two phases; first adaption phase with 1 g/L of propionate concentration and later, high-strength phase with 3 g/L. From 16s rRNA gene based metagenomics analysis of the former phase, four syntrophic microbial groups, Syntrophaceae, Syntrophomonadaceae, Methanobacterium and Methanosaeta were found to be dominant with complete degradation of propionate. The substrate accelerated microbial shifts were observed at high-strength phase with significant decrease of Syntrophaceae up to 26.9 %. Using Response Surface Methodology, pH 6.8-6.9 and temperature 34.5-34.9 C-omicron were found to be optimum growth conditions for the propionate degradation culture. Observed results could be useful to improve degradation efficiencies and obtained enriched culture can be used to recover propionate-accumulated digesters by bio-augmentation.11Nscopu

Enrichment of Anaerobic Propionate-oxidizing Consortia: Microbial Shifts and Kinetic Analysis

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Effect of Substrate-to-Inoculum Ratio and Temperatures During the Start-up of Anaerobic Digestion of Fish Waste

The high protein and lipid content of fish waste makes mono-digestion a difficult bioprocess for an anaerobic digestion (AD) system. On the other hand, the massive increase in fish and seafood consumption worldwide has led to an inevitable fish waste mono-AD. Therefore, this study was conducted to investigate the effects of food-to-microorganisms (F/M) ratios and temperatures during the start-up period of fish waste mono-digestion. F/M ratios of 0.5, 1, 2, and 3 on a g-COD/g-VSS basis were operated at 35°C and 45°C, representing mesophilic and hyper-mesophilic conditions, respectively. The increase in F/M ratio improved the maximum methane (CH4) production rate at both temperatures. However, F/M ratio of 0.5 generated the highest CH4 yield in mesophilic and hyper-mesophilic conditions (0.23±0.00 L-CH4/g-CODinput). Further increase in F/M ratio decreased CH4 yield up to 21.74% and 39.13% when the reactors were operated at 35°C and 45°C, respectively. When reactors were supplied with FM ratios of 0.5, 1, and 2, hyper-mesophilic temperature improved methanogenesis by up to 2.61% and shortened the lag phase by 22.88%. Meanwhile, F/M ratio 3 at 45°C decreased cumulative CH4 production by up to 26.57% and prolonged the lag phase by 10.19%. The result of this study is beneficial to managing the input substrate of a batch-AD system that treats fish waste as a sole substrate.11Nothe

Influence of Stepwise Increased Organic Loading on Anaerobic Mono-digestion of Dead Fish in Sequencing Batch Reactor Process

© 2022, The Author(s), under exclusive licence to Springer Nature B.V.Highly nutrient content dead fish (DF) waste can be considered a potentially valuable substrate for the anaerobic digestion (AD) to produce biogas. The effects of stepwise increased organic loading rate (OLR) on the process performance were investigated during mono-digestion of DF waste in anaerobic sequencing batch reactor mode. Two different sets of experiments have been conducted using whole dead fish (RDF) and boneless dead fish (RBDF) and OLR increased in five steps (1.95, 2.39, 2.73, 3.19, and 3.64 g VS/L/days) during the operational period. With the increasing of OLR, the biogas production rate increased by 79.07% and 58.20% at the end of the operation of RDF and RBDF, respectively. Higher alkalinity values throughout the experiment maintained stable pH values in between 7.87 to 8.01 for both RDF and RBDF. Total volatile fatty acids kept accumulating with the increasing OLR and the final concentrations were 7.69 ± 0.16 and 8.33 ± 0.19 g/L in RDF and RBDF, respectively. Overall, decreasing COD and VS removal efficiencies resulted in decreasing methane yields. The energy recovery rate was maintained at > 60% with the maximum OLR of 3.64 g VS/L/d of DF waste demonstrating its feasibility in the AD process as the only carbon source. Graphical Abstract: [Figure not available: see fulltext.].11Nsciescopu

Clogging detection in anaerobic co-digestion continuous system using machine learning approach

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음식물 쓰레기 및 슬러지의 혐기성 통합소화 시 어류 폐기물 투입의 영향

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