Background Cellulose is the most prevalent biomass and renewable energy source in nature. The hydrolysis of cellulosic biomass to glucose units is essential for the economic exploitation of this natural resource. Cellulase enzyme, which is largely generated by bacteria and fungus, is commonly used to degrade cellulose. Cellulases are used in a variety of industries, including bioethanol manufacturing, textiles, detergents, drugs, food, and paper. As part of our quest to find an efficient biocatalyst for the hydrolysis of cellulosic biomass, we describe the amplification, cloning, and sequencing of cellulase (cel9z) from Bacillus licheniformis strain Z9, as well as the characterization of the resulting enzyme. Results Cellulase was partially purified from B. licheniformis strain Z9 using (NH4)2SO4 precipitation and Sephadex G-100 gel column chromatography with 356.5 U/mg specific activity, 2.1-purification fold, and 3.07 % yield. The nucleotide sequence of the cellulase gene was deposited to the GenBank, B. licheniformis strain Z9 cellulase (cel9z) gene, under accession number MK814929. This corresponds to 1453 nucleotides gene and encodes for a protein composed of 484 amino acids. Comparison of deduced amino acids sequence to other related cellulases showed that the enzyme cel9z can be classified as a glycoside hydrolase family 9. SDS-PAGE analysis of the purified enzyme revealed that the molecular mass was 54.5 kDa. The optimal enzyme activity was observed at pH 7.4 and 30 °C. The enzyme was found to be strongly inhibited by Mg2+ and Na+, whereas strongly activated by Fe3+, Cu2+, and Ca2+. Conclusions B. licheniformis strain Z9 and its cellulase gene can be further utilized for recombinant production of cellulases for industrial application.

Ten heat resistant fungi, Arthrinium sp., Aspergillus cejpii, A. nidulans, A. spinosus, Byssochlamys nivea, Hamigera avellanea, Talaromyces trachyspermus, T. barcinensis, T. ucrainicus, and Trichoderma asperellum were tested on their ability to produce cellulolytic and pectinolytic enzymes. Except for B. nivea and A. cejpii, all species secreted cellulolytic enzymes in the used cup plate assay. All isolates produced considerable levels of pectinolytic enzymes, when investigated on a liquid pectin medium. The appearance of unexpected blue color in the pectin medium for some species was discussed, but further investigation is required to elucidate this phenomenon.

Cellulases are enzymes produced by many organisms and cellulose hydrolysis. They are well-known for their widely distributed industrial and medical uses. In this work, 84 bacterial strains were recovered from agar plates and 24 demonstrated hydrolyzing areas from carboxymethyl cellulose-containing agar dishes following Congo-Red staining. Among the 24 strains, three isolates Z7, Z9 and Z63 have shown increased activity of carboxymethyl cellulase (CMCase). It was shown that the three strains, Bacillus and Klebsiella, belonged to 2 separate genera. The isolates have been morphologically, physiologically, biochemically determined and validated by their 16S rRNA gene sequence. The 16S rRNA sequence of Z7, Z9 and Z63 has been submitted with GenBank under the accession codes (KT693283, KT693282 and KT693284). The sequences have been identified as Bacillus cereus strain Z7, Bacillus licheniformis strain Z9 and Klebsiella oxytoca strain Z63. This study gave appropriate information on the variety of rhizospheric isolated cellulose-degrading bacteria.