1,720,972 research outputs found
Enhancement of hydrolysis efficiency and biogas production by treatment of secondary sludge with bacteriophage lysozymes
No full textAnaerobic digestion of secondary sludge from wastewater treatment plants can degrade sludge while producing methane that can be burned as bioenergy. Hydrolysis of secondary sludge is the first step in anaerobic digestion, but is the rate-limiting step. In this study, to speed hydrolysis of secondary sludge, lysozymes from bacteriophage species T4, T7 and λ were applied to batch tests. The volatile suspended solids were removed by lysozymes at efficiencies of 23.6–50.1 %. Use of the lysozymes increased the reaction coefficient of biogasification of volatile suspended solids by 0.4–1.0 d−1, regardless of the origin of sludge, or sources of lysozyme. The removal efficiency of volatile suspended solids and methane yield had significantly positive correlation (p < 0.001). Relative abundances of genera Simplicispira (10.3 → 5.2 %), Dokdonella (4.9 → 3.9 %), and Thermomonas (2.7 → 1.2 %) were high in original secondary sludge, and maintained relative abundance over other genera even after lysozyme treatment. To increase the ratio of microbes to organics, sludge samples from various sources were aerated and cultivated with 40 g/L glucose. In experiments on this cultivated sludge, Klebsiella (3.7 → 23.0 %) Kosakonia (1.8 → 19.0 %) and Dysgonomonas (0.0 → 15.3 %) sharply increased after lysozyme treatment, due to their fast growth. Treatment with bacteriophage lysozymes can significantly increase sludge reduction. © 202211Nsciescopu
Bloom of Methanospirillum in Food-wastewater Treating Anaerobic Digestion Reactor after organic acid accumulation
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Monitoring microbial community structure and variations in a full-scale petroleum refinery wastewater treatment plant
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Effect of seed bacterial community and diversity on the carbohydrate degradation in anaerobic digestion
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Shift in bacterial diversity in acidogenesis of gelatin and gluten seeded with various anaerobic digester inocula
No full textThe aim of this study was to investigate divergence of bacteria degrading model proteins of food-processing wastewater. Gelatin and gluten were used as substrate to represent animal and plant proteins from food wastes, respectively. The inocula were obtained from eight full-scale anaerobic digestion reactors. Food-to-microorganism ratio was 3 g chemical oxygen demand equivalent of substrate per 1 g volatile suspended solids of inoculum. A first-order reaction model revealed reaction constants ranged 1.34 ≤ k ≤ 2.30 d−1 for gelatin and 0.63 ≤ k ≤ 1.69 d−1 for gluten. Metagenomic analysis of 16s rRNA sequences showed that dominant bacteria after gelatin degradation batch were different for each inocula. Klebsiella aerogenes, Hathewaya, Peptoclostridium, or Clostridium collagenovorans were most abundant. Klebsiella aerogenes was the most abundant species after gluten degradation for all inocula.11Nsciescopu
Magnetite as an enhancer in methanogenic degradation of volatile fatty acids under ammonia-stressed conditions
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Shift in methanogenic community in protein degradation using different inocula
No full textAnaerobic digestion (AD) of protein-rich wastes is problematic due to production of ammonia and hydrogen sulfide. In this work, eight inocula were used in batch AD of solutions of gelatin and gluten at 3 g COD substrate/ 1g VSS inoculum. AD plants from which inocula originated were treating food waste or food wastewater, wastewater sludge, or a combination of them. Inocula were evaluated by fitting methane production data using the modified Gompertz model. Sequencing of 16 s rRNA of microorganisms showed that Methanoculleus was dominant in inocula from plants that were treating food waste, and Methanosaeta was dominant in the others. The maximum methane production rate varied by a factor of three for each substrate: 2.734-7.438 mLCH4 gCOD1 d-1 for gelatin, and 1.950 to 5.532 mLCH4 gCOD-1 d-1 for gluten. This study demonstrates that inoculum must be chosen appropriately when treating proteinaceous waste by AD.11Nsciescopu
Comparison of Microbial Communities in Anaerobic Digestion Inoculums by Protein Degradation
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