Cellulolytic Bacillus strains from natural habitats - A review

Fossil fuel reserves depletion, global warming, costly and problematic waste recycling and population growth greatly induce to fi nd renewable energy sources. Second generation bioethanol produced from lignocellulosic materials exhibits great potential as liquid biofuel to substitute gasoline. Production costs of enzymes involved in cellulose hydrolysis into fermentable sugars represent the main obstacle to achieve competitive production of cellulosic ethanol. Cheaper and more effi cient biocatalysts for the saccharifi cation step are, therefore, required for making the whole process more competitive. The biodiversity of natural niches has been so far exploited for the isolation of new cellulolytic microorganisms whose enzymes are naturally evolved for an effi cient conversion of cellulose into fermentable sugars. This review discusses advances in isolation of bacteria, namely Bacillus spp., from several natural habitats and their ability to produce cellulase activity.