An extremely alkaline novel chitinase from Streptomyces sp. CS495

•A microbial chitinase was isolated, purified and biochemically characterized.•Ch495 is thermostable, alkaline and stable in broad range of pH.•Ch495 releases N-acetyl d-glucosamine (GlcNAc), diacetylchitobiose (GlcNAc)2 and trace amount of triacetlychitotrose (GlcNAc)3 whereas (GlcNAc)2 was the major oligosaccharide.•Ch495 shows antifungal activity against Fusarium solani (KCCM 12055) and Aspergillus brasiliensis (ATCC 16404).

An extremely alkaline chitinase from Streptomyces sp. CS495 was isolated from a Korean soil sample, purified by single-step chromatography, and biochemically characterized. The extracellular chitinase was purified 7.0 fold with a 33.9% yield by Sepharose Cl-6B column. The molecular mass of the enzyme (Ch495) was approximately 41 kDa. Ch495 was found to be stable over a broad pH range (5–12.5) and to 50 °C and have an optimum temperature of 60 °C. Ch495 had Km and Vmax values of 1.34 ± 2.9 mg/mL and 889 ± 3.6 mmol/min, respectively using different concentrations of colloidal chitin. N-terminal sequence of Ch495 was APREKINLLYFLGYF. HPLC and TLC analysis of Ch495 shows the production of produced N-acetyl d-glucosamine (GlcNAc) as minor and diacetylchitobiose (GlcNAc)2 as major products. Ch495 shows antifungal activity against Fusarium solani and Aspergillus brasiliensis which can be used for the biological control of fungus. As being simple in purification, extreme alkalophilic, stable in broad range of pH, ability to produce oligosaccharides, and antifungal activity shows that Ch495 has potential applications in industries as for chitooligosaccharides production used as medical prebiotics or/and for the biological control of plant pathogens in agriculture.