Singh Suniti, Keating Ciara, Ijaz Umer Zeeshan, Hassard Francis
Cranfield Water Science Institute, Cranfield University, College Way, Bedfordshire MK43 0AL, UK.
School of Biodiversity, One Health and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK.
Sci Total Environ. 2023 May 20;874:162420. doi: 10.1016/j.scitotenv.2023.162420. Epub 2023 Feb 24.
Fats, oil and grease, and their hydrolyzed counterparts-long chain fatty acids (LCFA) make up a large fraction of numerous wastewaters and are challenging to degrade anaerobically, more so, in low temperature anaerobic digestion (LtAD) systems. Herein, we perform a comparative analysis of publicly available Illumina 16S rRNA datasets generated from LCFA-degrading anaerobic microbiomes at low temperatures (10 and 20 °C) to comprehend the factors affecting microbial community dynamics. The various factors considered were the inoculum, substrate and operational characteristics, the reactor operation mode and reactor configuration, and the type of nucleic acid sequenced. We found that LCFA-degrading anaerobic microbiomes were differentiated primarily by inoculum characteristics (inoculum source and morphology) in comparison to the other factors tested. Inoculum characteristics prominently shaped the species richness, species evenness and beta-diversity patterns in the microbiomes even after long term operation of continuous reactors up to 150 days, implying the choice of inoculum needs careful consideration. The generalised additive models represented through beta diversity contour plots revealed that psychrophilic bacteria RBG-13-54-9 from family Anaerolineae, and taxa WCHB1-41 and Williamwhitmania were highly abundant in LCFA-fed microbial niches, suggesting their role in anaerobic treatment of LCFAs at low temperatures of 10-20 °C. Overall, we showed that the following bacterial genera: uncultured Propionibacteriaceae, Longilinea, Christensenellaceae R7 group, Lactivibrio, candidatus Caldatribacterium, Aminicenantales, Syntrophus, Syntrophomonas, Smithella, RBG-13-54-9, WCHB1-41, Trichococcus, Proteiniclasticum, SBR1031, Lutibacter and Lentimicrobium have prominent roles in LtAD of LCFA-rich wastewaters at 10-20 °C. This study provides molecular insights of anaerobic LCFA degradation under low temperatures from collated datasets and will aid in improving LtAD systems for treating LCFA-rich wastewaters.
脂肪、油脂及其水解产物——长链脂肪酸（LCFA）在众多废水中占比很大，并且在厌氧条件下降解具有挑战性，在低温厌氧消化（LtAD）系统中更是如此。在此，我们对公开可用的Illumina 16S rRNA数据集进行了比较分析，这些数据集来自低温（10和20°C）下降解LCFA的厌氧微生物群落，以了解影响微生物群落动态的因素。所考虑的各种因素包括接种物、底物和操作特性、反应器运行模式和反应器配置以及测序的核酸类型。我们发现，与其他测试因素相比，降解LCFA的厌氧微生物群落主要通过接种物特性（接种物来源和形态）来区分。即使在连续反应器长期运行长达150天后，接种物特性仍显著塑造了微生物群落中的物种丰富度、物种均匀度和β-多样性模式，这意味着接种物的选择需要仔细考虑。通过β多样性等高线图表示的广义相加模型显示，厌氧绳菌科的嗜冷细菌RBG-13-54-9以及分类群WCHB1-41和威廉氏杆菌属在以LCFA为食的微生物生态位中高度丰富，表明它们在10-20°C低温下对LCFA进行厌氧处理中发挥作用。总体而言，我们表明以下细菌属：未培养的丙酸杆菌科、长绳菌属、克里斯滕森菌科R7组、乳酸弧菌属、候选热杆菌属、氨基厌氧杆菌目、互营菌属、互营单胞菌属、史密斯菌属、RBG-13-54-9、WCHB1-41、动球菌属、解朊菌属、SBR1031、 Lutibacter和细枝杆菌属在10-20°C下对富含LCFA的废水进行LtAD过程中发挥着重要作用。这项研究从整理的数据集中提供了低温下厌氧LCFA降解的分子见解，并将有助于改进用于处理富含LCFA废水的LtAD系统。
