ABSTRACT

In the present study, we developed several microflora communities that utilize digested sludge (DS), the recalcitrant waste product of anaerobic digestion, as a substrate for biogas production with the aim of their future application to DS recycling. Strict enrichment with DS as the sole nutrient source was introduced to culture microbes from soil and herbivore dung samples; microflora communities promoting stable levels of biogas production were obtained. The average methane and hydrogen yield from soil-derived microflora were 4.86 and 0.94 ml per 1.0 g DS, respectively. Notably, two microflora communities enriched from a riverbank sediment produced 20.79 ml and 14.10 ml methane from 1.0 g DS. By contrast, the methane and hydrogen yield for herbivore dung-derived microfloras were on average 1.31 ml and 1.87 ml per 1.0 g DS, respectively. Potent hydrogen-biogas producers were obtained from rabbit (4.12 ml per 1.0 g DS), goat (3.16 ml per 1.0 g DS), and sheep dung (2.52 ml per 1.0 g DS). The cultured microflora communities included representatives from the eubacterial genera, Clostridiaceae and Eubacteriaceae together with several anaerobic genera. Pseudomonas spp. are found in the riverbank sediment-derived microfloras, suggesting that the floras employ syntrophic acetate oxidation and hydrogentrophic methanogenesis (SAO-HM) pathway for methane production. The methanogenic microflora communities were dominated by bacteria from the Methanobacteriaceae family and unclassified archaea. Moreover, ascomycetous fungi and protists were found, implying that they act as oxygen scavengers and bacterial grazers, respectively. Enzymatic analysis suggested that the microfloras hydrolyze DS via cellulase, chitinase, and protease activities.

摘要

在本研究中，我们开发了几个利用消化污泥 (DS)（厌氧消化的顽固废物）作为沼气生产基质的微生物群落，旨在将其应用于 DS 回收。将DS作为唯一营养源的严格富集引入土壤和食草动物粪便样本中培养微生物；获得了促进稳定的沼气生产水平的微生物群落。来自土壤微生物区系的平均甲烷和氢气产量分别为每 1.0 g DS 4.86 和 0.94 ml。值得注意的是，从河岸沉积物中富集的两个微生物群落从 1.0 g DS 中产生了 20.79 ml 和 14.10 ml 甲烷。相比之下，草食动物粪便衍生微生物群的甲烷和氢气产量平均分别为每 1.0 g DS 1.31 ml 和 1.87 ml。从兔子（每 1.0 g DS 4.12 毫升）、山羊（每 1.0 g DS 3.16 毫升）和绵羊粪（每 1.0 g DS 2.52 毫升）中获得有效的氢气-沼气生产者。培养的微生物群落包括真细菌属的代表，梭菌科和真杆菌科以及几个厌氧属。假单胞菌属 在河岸沉积物衍生的微生物群落中发现，表明这些植物群采用同养乙酸盐氧化和氢营养产甲烷（SAO-HM）途径进行甲烷生产。产甲烷微生物群落以甲烷杆菌科细菌和未分类的古细菌为主。此外，还发现了子囊菌类真菌和原生生物，这意味着它们分别充当氧气清除剂和细菌食草动物。酶学分析表明，微生物群落通过纤维素酶、几丁质酶和蛋白酶活性水解 DS。