Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen, 40002, Thailand.
International College, Thaksin University, Songkhla, 90000, Thailand.
Sci Rep. 2023 Feb 20;13(1):2968. doi: 10.1038/s41598-023-29895-0.
Lignocellulosic biomass is a promising substrate for biogas production. However, its recalcitrant structure limits conversion efficiency. This study aims to design a microbial consortium (MC) capable of producing the cellulolytic enzyme and exploring the taxonomic and genetic aspects of lignocellulose degradation. A diverse range of lignocellulolytic bacteria and degrading enzymes from various habitats were enriched for a known KKU-MC1. The KKU-MC1 was found to be abundant in Bacteroidetes (51%), Proteobacteria (29%), Firmicutes (10%), and other phyla (8% unknown, 0.4% unclassified, 0.6% archaea, and the remaining 1% other bacteria with low predominance). Carbohydrate-active enzyme (CAZyme) annotation revealed that the genera Bacteroides, Ruminiclostridium, Enterococcus, and Parabacteroides encoded a diverse set of cellulose and hemicellulose degradation enzymes. Furthermore, the gene families associated with lignin deconstruction were more abundant in the Pseudomonas genera. Subsequently, the effects of MC on methane production from various biomasses were studied in two ways: bioaugmentation and pre-hydrolysis. Methane yield (MY) of pre-hydrolysis cassava bagasse (CB), Napier grass (NG), and sugarcane bagasse (SB) with KKU-MC1 for 5 days improved by 38-56% compared to non-prehydrolysis substrates, while MY of prehydrolysed filter cake (FC) for 15 days improved by 56% compared to raw FC. The MY of CB, NG, and SB (at 4% initial volatile solid concentration (IVC)) with KKU-MC1 augmentation improved by 29-42% compared to the non-augmentation treatment. FC (1% IVC) had 17% higher MY than the non-augmentation treatment. These findings demonstrated that KKU-MC1 released the cellulolytic enzyme capable of decomposing various lignocellulosic biomasses, resulting in increased biogas production.
木质纤维素生物质是沼气生产的有前途的底物。然而，其顽固的结构限制了转化效率。本研究旨在设计一种能够产生纤维素酶的微生物群落（MC），并探索木质纤维素降解的分类和遗传方面。从各种生境中富集了各种木质纤维素降解细菌和降解酶，用于已知的 KKU-MC1。发现 KKU-MC1 在拟杆菌门（51%）、变形菌门（29%）、厚壁菌门（10%）和其他门（8%未知、0.4%未分类、0.6%古菌和其余 1%其他低优势细菌）中丰富。碳水化合物活性酶（CAZyme）注释表明，拟杆菌属、真杆菌属、肠球菌属和副拟杆菌属的属编码了一系列不同的纤维素和半纤维素降解酶。此外，与木质素解构相关的基因家族在假单胞菌属中更为丰富。随后，通过两种方式研究了 MC 对各种生物质产甲烷的影响：生物强化和预水解。与非预水解底物相比，用 KKU-MC1 对预处理的木薯渣（CB）、象草（NG）和甘蔗渣（SB）进行 5 天预水解后，甲烷产量（MY）提高了 38-56%，而用 KKU-MC1 对预处理的滤饼（FC）进行 15 天预水解后，MY 提高了 56%与原始 FC 相比。在 KKU-MC1 强化下，CB、NG 和 SB（初始挥发性固体浓度（IVC）为 4%）的 MY 提高了 29-42%与非强化处理相比。FC（1% IVC）的 MY 比非强化处理高 17%。这些发现表明，KKU-MC1 释放出能够分解各种木质纤维素生物质的纤维素酶，从而提高沼气产量。
