Behera Sudhanshu S, Ray Ramesh C
Department of Biotechnology and Medical Engineering, National Institute of Technology, Rourkela 769008, India.
ICAR-Central Tuber Crops Research Institute (Regional Centre), Bhubaneswar 751 019, India.
Int J Biol Macromol. 2016 May;86:656-69. doi: 10.1016/j.ijbiomac.2015.10.090. Epub 2015 Nov 19.
Lignocellulose is the most plentiful non-food biomass and one of the most inexhaustible renewable resources on the planet, which is an alternative sustainable energy source for the production of second generation biofuels. Lignocelluloses are composed of cellulose, hemicellulose and lignin, in which the sugar polymers account for a large portion of the biomass. Cellulases belong to the glycoside hydrolase family and catalyze the hydrolysis of glyosidic linkages depolymerizing cellulose to fermentable sugars. They are multi-enzymatic complex proteins and require the synergistic action of three key enzymes: endoglucanase (E.C. 3.2.1.4), exoglucanase (E.C. 3.2.1.176) (E.C. 3.2.1.91) and β-glucosidase (E.C. 3.2.1.21) for the depolymerization of cellulose to glucose. Solid state fermentation, which holds growth of microorganisms on moist solid substrates in the absence of free flowing water, has gained considerable attention of late due its several advantages over submerged fermentation. The review summarizes the critical analysis of recent literature covering production of cellulase in solid state fermentation using advance technologies such as consolidated bioprocessing, metabolic engineering and strain improvement, and circumscribes the strategies to improve the enzyme yield.
木质纤维素是地球上最丰富的非粮食生物质和最取之不尽的可再生资源之一，是生产第二代生物燃料的一种可持续替代能源。木质纤维素由纤维素、半纤维素和木质素组成，其中糖聚合物占生物质的很大一部分。纤维素酶属于糖苷水解酶家族，催化糖苷键水解，将纤维素解聚为可发酵糖。它们是多酶复合蛋白，需要三种关键酶协同作用：内切葡聚糖酶（E.C. 3.2.1.4）、外切葡聚糖酶（E.C. 3.2.1.176）（E.C. 3.2.1.91）和β-葡萄糖苷酶（E.C. 3.2.1.21），才能将纤维素解聚为葡萄糖。固态发酵是指在没有自由流动水的情况下，微生物在潮湿固体基质上生长，由于其相对于深层发酵具有多种优势，近来受到了广泛关注。本文综述了近期文献中关于使用整合生物加工、代谢工程和菌株改良等先进技术在固态发酵中生产纤维素酶的批判性分析，并概述了提高酶产量的策略。
