Title
Biodiversity of cellulase producing bacteria and their applications
Authors
NADEEM AKHTAR AANCHAL DINESH GOYAL and ARUN GOYAL

Received August 30, 2014
Published Volume 50 Issue 9-10 October-December
Keywords Bacillus sp., biodiversity, cellulase, hemicellulose

Abstract
Bioconversion of cellulose, mainly by bacteria and fungi, plays a key role in the global carbon cycle. The biodiversity of these microorganisms in nature is due to diverse cellulosic substrates and geoclimatic conditions, but despite their abundance, only a few are efficiently involved in the biodegradation process. Bacterial cellulase is preferred over fungal one, owing to the higher bacterial growth rate, broad range of tolerance, synergy of the complex enzyme system, higher compatibility and feasibility towards genetic engineering. This paper reviews the diversity of aerobic and anaerobic cellulolytic bacteria, their cellulase activity, stability and application in biodegradation of lignocelluloses in various industries. Most of the cellulolytic bacteria belong to phyla Actinobacteria, Bacteroidetes, Fibrobacteres, Firmicutes and Proteobacteria. Among aerobic bacteria, members of Bacillaceae and Paenibacillaceae families mainly inhabit soil, cowdung and compost. However, anaerobic species of Clostridia have mostly been reported to originate from sediments of hot springs, soil and compost, whereas Butyrivibrio, Fibrobacter, Halocella and Ruminococcus are found in rumen. Purified bacterial cellulases generally have wide pH and temperature tolerance and a molecular mass in the range of 30-250 kDa. Efforts have been made to increase cellulase activity, all with limited success. Extremophilic bacteria, such as Acidothermus cellulolyticus, Clostridium straminisolvens, Geobacillus pallidus, Sporotrichum thermophile, Thermobifida fusca, Thermomonospora curvata and Rhodothermus marinus, have proved to be a better choice for cellulase production to improve the process economics for various industrial applications.