Maki Miranda L, Idrees Amna, Leung Kam Tin, Qin Wensheng
Biorefining Research Institute, Lakehead University, Thunder Bay, Ont., Canada.
J Mol Microbiol Biotechnol. 2012;22(3):156-66. doi: 10.1159/000341107. Epub 2012 Jul 24.
This study focuses on the isolation and characterization of bacteria from municipal waste and peat to determine those bacteria with good potential for modification and decomposition of lignocellulosic biomass for industrial application. Twenty cellulase-producing bacteria belonging to four major phyla - Firmicutes, Actinobacteria, Proteobacteria and Bacteroidetes - were found when screened on carboxymethyl cellulose-containing agar. Six isolates also exhibited activities towards filter paper as the sole carbon source in salt media, while 12 exhibited activities towards xylan when screened on xylan-containing plates. Moreover, 5 isolates survived in and increased the absorbance of 1% black liquor in salt media by an average of 2.07-fold after 21 days of incubation. Similarly, these 5 isolates increased the absorbance of 0.1% pure lignin at 280 nm in salt media, indicating modification of lignin. Additionally, the Fourier transform infrared spectroscopy analysis of 1% barley straw treated for 21 days with these 5 strains showed a preference for consumption of hemicelluloses over lignin; however, a change in lignin was observed. A Bacillus strain (55S5) and a Pseudomonas strain (AS1) displayed the greatest potential for lignocellulose decomposition due to a variety of cellulase activities, as well as xylanase activity and modification of lignin. Several of these isolates have good potential for industrial use in the degradation of lignocellulosic biomass.
本研究聚焦于从城市垃圾和泥炭中分离细菌并对其进行表征，以确定那些在工业应用中对木质纤维素生物质具有良好改性和分解潜力的细菌。在含羧甲基纤维素的琼脂培养基上进行筛选时，发现了属于四个主要门类——厚壁菌门、放线菌门、变形菌门和拟杆菌门——的20株产纤维素酶细菌。有6株分离菌在以滤纸作为盐培养基中唯一碳源时也表现出活性，而在含木聚糖的平板上筛选时，有12株对木聚糖表现出活性。此外，5株分离菌在盐培养基中能在1%的黑液中存活，培养21天后，其吸光度平均增加了2.07倍。同样，这5株分离菌在盐培养基中使0.1%纯木质素在280nm处的吸光度增加，表明木质素发生了改性。另外，用这5株菌株对1%大麦秸秆处理21天的傅里叶变换红外光谱分析表明，相比于木质素，这些菌株更倾向于消耗半纤维素；不过，观察到了木质素的变化。一株芽孢杆菌菌株（55S5）和一株假单胞菌菌株（AS1）由于具有多种纤维素酶活性、木聚糖酶活性以及木质素改性能力，在木质纤维素分解方面表现出最大潜力。这些分离菌中的几种在木质纤维素生物质降解的工业应用方面具有良好潜力。
