Poszytek Krzysztof, Ciezkowska Martyna, Sklodowska Aleksandra, Drewniak Lukasz
Laboratory of Environmental Pollution Analysis, Faculty of Biology, University of Warsaw Warsaw, Poland.
Front Microbiol. 2016 Mar 15;7:324. doi: 10.3389/fmicb.2016.00324. eCollection 2016.
The use of lignocellulosic biomass as a substrate in agricultural biogas plants is very popular and yields good results. However, the efficiency of anaerobic digestion, and thus biogas production, is not always satisfactory due to the slow or incomplete degradation (hydrolysis) of plant matter. To enhance the solubilization of the lignocellulosic biomass various physical, chemical and biological pretreatment methods are used. The aim of this study was to select and characterize cellulose-degrading bacteria, and to construct a microbial consortium, dedicated for degradation of maize silage and enhancing biogas production from this substrate. Over 100 strains of cellulose-degrading bacteria were isolated from: sewage sludge, hydrolyzer from an agricultural biogas plant, cattle slurry and manure. After physiological characterization of the isolates, 16 strains (representatives of Bacillus, Providencia, and Ochrobactrum genera) were chosen for the construction of a Microbial Consortium with High Cellulolytic Activity, called MCHCA. The selected strains had a high endoglucanase activity (exceeding 0.21 IU/mL CMCase activity) and a wide range of tolerance to various physical and chemical conditions. Lab-scale simulation of biogas production using the selected strains for degradation of maize silage was carried out in a two-bioreactor system, similar to those used in agricultural biogas plants. The obtained results showed that the constructed MCHCA consortium is capable of efficient hydrolysis of maize silage, and increases biogas production by even 38%, depending on the inoculum used for methane fermentation. The results in this work indicate that the mesophilic MCHCA has a great potential for application on industrial scale in agricultural biogas plants.
在农业沼气厂中，使用木质纤维素生物质作为底物非常普遍且效果良好。然而，由于植物物质的降解（水解）缓慢或不完全，厌氧消化效率以及沼气产量并不总是令人满意。为了提高木质纤维素生物质的溶解性，人们采用了各种物理、化学和生物预处理方法。本研究的目的是筛选和鉴定纤维素降解细菌，并构建一个专门用于降解玉米青贮饲料并提高该底物沼气产量的微生物群落。从污水污泥、农业沼气厂的水解器、牛粪浆和粪便中分离出了100多株纤维素降解细菌。在对分离菌株进行生理特性鉴定后，选择了16株（芽孢杆菌属、普罗威登斯菌属和慢生根瘤菌属的代表菌株）构建具有高纤维素分解活性的微生物群落，称为MCHCA。所选菌株具有较高的内切葡聚糖酶活性（超过0.21 IU/mL CMC酶活性），并且对各种物理和化学条件具有广泛的耐受性。在类似于农业沼气厂使用的双生物反应器系统中，使用所选菌株对玉米青贮饲料进行降解的实验室规模沼气生产模拟。获得的结果表明，构建的MCHCA群落能够有效水解玉米青贮饲料，根据用于甲烷发酵的接种物不同，沼气产量甚至可提高38%。这项工作的结果表明，嗜温MCHCA在农业沼气厂的工业规模应用中具有巨大潜力。
