Whole genome sequencing of a novel chitinolytic Streptomyces sp. RB7AG reveals it's chitosan production potential: optimization of the process through Taguchi experimental design.

This study reports about the De novo whole genome sequencing and analysis of a bacterial isolate Streptomyces sp. Strain. RB7AG, isolated from the sediments of Chilika Lake, Odisha, India. The genome report in this paper highlights a size of 7,708,681 bp and a GC content of 72.3%. It also consists of 7274 coding sequence, 66 tRNA and 4 rRNA. Furthermore, carbohydrate active enzyme analysis revealed that the strain RB7AG has 127 glycoside hydrolase family genes, which is well known for hydrolysis of glycosidic bond in complex sugars. Thus, exploiting these microorganisms for the production of chitosan can be an appropriate waste disposal method of choice. Chitosan being an important biomolecule that has various industrial applications. Hence, the study also sought to improve the culture conditions for the Streptomyces sp. strain RB7AG for generation, recovery, and characterization of chitosan. Utilizing the isolate, various low-cost nitrogen sources, including peptone, yeast extract, ammonium chloride, urea along with pH, media, metal ions and surfactant were assessed for chitosan synthesis. In this context, traditional methods such as One Factor One Time are more time consuming and expensive too. The current work aims to establish a methodology to optimize the degradation of chitin by the chitinolytic Streptomyces sp. strain RB7AG, isolated from lake sediment for the production of chitosan. More than one factor was considered at the time of experiments, and the knowledge was integrated into Taguchi statistical design to determine the contribution of the most important factors required to achieve the desired end product i.e. chitosan. Highest chitosan production (2.188 µg/ml) was observed in MSM media, 1.0% NaCl (w/v), 0.5% Yeast extract, 1% Ca2+ and 0.1% Tween 80 at pH 9. The whole genome analysis of RB7AG would help in determining the mechanism involved in the breakdown activity. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03613-z.

Exploration of genomic and functional features of chitinolytic bacterium Streptomyces chilikensis RC1830, isolated from Chilika Lake, India.

Streptomyces chilikensis RC1830 was previously isolated as a novel chitinolytic streptomycete from Chilika Lake, Odisha, India. The strain RC1830 is a representative member of the soil-dwelling, filamentous Streptomyces group that produces the majority of natural antibiotics and secondary metabolites. The objective of this work was to assess the chitin degradation ability and whole-genome sequence of Streptomyces chilikensis RC1830. TLC analysis of the fermentation product revealed that strain RC1830 can convert shrimp shell colloidal chitin to N-acetylated chitooligosaccharides (N-AcCOS). A genome-wide investigation of RC1830 was also carried out to investigate the genetic basis for chitin breakdown. The result showed that the RC1830 genome possesses a chromosome with 7,121,774 bp (73.2% GC). The genome consists of 6807 coding sequences, 69 tRNA, and 3 rRNA genes. Furthermore, carbohydrate-active enzyme (CAZyme) analysis revealed that RC1830 has 89 glycoside hydrolase family genes, which could modulate the enzymes involved in the degradation of chitin ultimately producing industrially important COS. The whole-genome information of RC1830 could emphasize the mechanism involved in the RC1830's chitin breakdown activity, endowing RC1830 with a promising alternative for COS production. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-022-03184-5.