Evaluation and characterization of a cellulolytic activity from a newly isolated thermophilic Alicyclobacillus sp.

Cellulolytic enzymes of microbial origin play an important role in bioconversion processes of lignocellulosic materials, the most available renewable resource on Earth, continuously produced as a result of agricultural, industrial and forestry manufactures. One of major drawbacks in industrial terms is that most cellulases lack of thermostability and, as consequence, thermophilic microorganisms have received considerable attention as sources of highly active and thermostable cellulolytic enzymes. In particular, the bacteria of the genus Bacillus are regarded as attractive industrial organisms that thrive also at temperatures higher than 60°C and produce high titers of a great variety of extracellular enzymes. In a recent screening for thermophilic bacteria from Azores hot springs, a microbial strain, exhibiting cellulase activity, was isolated. The identification through 16S rRNA gene analysis revealed that the microorganism belongs to the Alicyclobacillus genus. The cellulolytic activity production was detected after growing the microorganism at 65°C and pH 3.0, onto solid medium and in liquid culture both containing carboxymethyl cellulose as the sole carbon source. Moreover, the kinetics of bacterial growth and extracellular cellulase production were evaluated followed by the enzyme characterization. The preliminary results indicated that the cellulase from this novel Alicyclobacillus strain might be a good candidate for cellulose enzymatic hydrolysis processes.