Jannat Md Abu Hanifa, Lee Jangwoo, Shin Seung Gu, Hwang Seokhwan
Division of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk, South Korea.
Department of Energy Engineering, Future Convergence Technology Research Institute, Gyeongnam National University of Science and Technology, Jinju, Gyeongnam, South Korea.
J Hazard Mater. 2021 Jan 5;401:123230. doi: 10.1016/j.jhazmat.2020.123230. Epub 2020 Jun 17.
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 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.
丙酸盐是厌氧消化池中一种在数量上很重要的产甲烷中间产物，只有数量有限的微生物能够在与产甲烷菌的互营联合作用下利用它。已知互营丙酸盐氧化细菌由于能量产量低而生长缓慢。因此，丙酸盐在厌氧消化池中经常积累，并且会对消化池性能产生负面影响。在本研究中，来自四个不同接种源的丙酸盐降解菌群在两阶段的序批式培养模式中得到富集；第一阶段为适应期，丙酸盐浓度为1 g/L，随后是高强度期，丙酸盐浓度为3 g/L。基于16s rRNA基因的宏基因组学分析表明，在前一阶段，四个互营微生物类群，即互营杆菌科、互营单胞菌科、甲烷杆菌属和甲烷丝状菌属占主导地位，丙酸盐完全降解。在高强度期观察到底物加速了微生物群落的变化，互营杆菌科显著减少，降幅高达26.9%。使用响应面法，发现pH 6.8 - 6.9和温度34.5 - 34.9℃是丙酸盐降解培养物的最佳生长条件。观察结果可能有助于提高降解效率，获得的富集培养物可用于通过生物强化来恢复积累了丙酸盐的消化池。
