Characterization of chitinase‐producing Serratia and Bacillus strains isolated from insects

Abstract

Chitinases (EC 3.2.1.14) are enzymes that hydrolyze chitin by cleaving β‐1,4 N‐glycosidic bonds. These enzymes have been used for multiple applications in biotechnology, especially for controlling insect pests and phytopathogenic fungi. In the present study, we isolated two chitinase‐producing bacteria strains from insects (strain SCH‐1 from Moechotypa diphysis and strain SCH‐2 from Sphedanolestes impressicollis). Serratia sp. SCH‐1 was a short, rod‐shaped facultative anaerobe, while Bacillus strain SCH‐2 was a rod‐shaped endospore‐forming anaerobe. Strains SCH‐1 and SCH‐2 were identified as Serratia sp. and Bacillus sp., respectively based on 16S rRNA gene sequencing. Strain SCH‐1 shared maximum homology (99.44%) with Serratia nematodiphila DZ0503SBS1 and Serratia marcescens subsp. sakuensis KRED. Strain SCH‐2 had a maximum homology of 99.24% with Bacillus thuringiensis ATCC 10792 and Bacillus toyonensis BCT‐7112. Serratia sp. SCH‐1 contained greater levels of saturated fatty acids, but the concentration of branched acids, especially iso‐C15:0, was highest in Bacillus sp. SCH‐2. Serratia sp. SCH‐1 possessed chitinase activity of 1.59 unit/mg protein after 5 days of incubation in culture medium. In contrast, Bacillus sp. SCH‐2 had a maximum activity of 0.84 unit/mg protein after 4 days of incubation. Chitinase isozymes produced by Serratia sp. SCH‐1 appeared as five bands with sizes of 20, 26, 36, 45 and 54 kDa. Bacillus sp. SCH‐2 showed a chitinase isozyme profile with three bands having sizes of 36, 45 and 50 kDa on SDS‐PAGE gels.

Selection of Chitinolytic Bacteria as Biological Control of Colletotrichum capsici

“…Those isolates were KAHN 15.12 and SAHA 12.12. A clear zone of hydrolytic indicated chitin degradation by chitinase-producing bacteria (Han et al, 2014). Incompatibility of chitinolytic index with the percentage inhibition of fungal pathogens proved that the two are not interconnected.…”

“…and Bacillus sp. (Asril et al, 2014;Han et al, 2014). Chitinase activities had increased in the stationary phase due to the decrease of nutrients in the media, so chitinase was secreted in high quantities.…”

Histopathological , Enzyme - Histochemical and Immunohistochemical Diagnosis of Mast Cell Tumors in the Skin of Golden Hamster

“…and Bacillus sp. were isolated from insects and both bacterial strains produced chitinase enzyme in colloidal chitin medium (Han et al 2014). The Chi gene in the genomic DNA of Rn9 (B. subtilis) and Rn13 (Serratia sp.)…”

“…Chitinase enzymes could be used and useful for multiple applications in biotechnology, especially for controlling insect pests and phytopathogenic fungi (Han et al 2014). In the present study we used the chitinase enzyme from B. subtilisstrain to control tomato leaf miner insect T. absoluta.…”

Bioformation of N-Acetylglucosamine from Shrimp Shell Chitin by Serratia marcescens PT-6 Cultured in various pH and Temperature

“…Hal tersebut sesuai dengan Hardjito et al (2007) yang menyatakan bahwa Serratia marcescens dapat hidup pada kisaran pH 5 sampai 11. Begitu juga dengan Han et al (2014) yang menyatakan bahwa bakteri Serratia sp. SCH-1 yang diisolasi dari serangga di pegunungan kawasan Gambar 3.…”