The ability of Bacillus safensis to synthesize xylanase and other industrially important enzymes utilizing lignocellulosic biomass makes it advantageous for a variety of biotechnology applications. Thus, the current investigation aimed to optimize conditions and medium components for maximizing xylanase production by a newly isolated Bacillus safensis strain using banana rachis (peel of banana tree) as a novel source of carbon.

Upon employing Box-Behnken Design (BBD) statistical approach, the highest enzyme activity was obtained 25.24 U/ml at 2 g/L banana rachis, 1 g/L yeast extract, 1 g/L K2HPO4, 5 g/L NaNO3, 35°C and 72 h of incubation time. The purified enzyme showed 10 times higher enzyme activity (143.6 U/ml) with 2.3 mg/ml protein concentration. The enzyme was found to maintain stability up to 60°C in a wide range of pH (6 to 10). Analysis of whole genome sequencing data revealed the presence of xylanase production and xylan metabolic genes (xynA, xynB, xylP, xylT) on Bacillus safensis FB03. Also, from genome annotation, different carbohydrate metabolic genes such as glycoside hydrolases (GH), glycosyl transferases (GT), polysaccharide lyases (PL), carbohydrate esterases (CE), auxiliary activities (AA), and carbohydrate binding modules (CBM) were identified.

In accordance to our research, banana rachis can be considered as a major medium component to develop economical fermentation process for the production of xylanase by Bacillus safensis FB03. Additionally, identification of genomic location of xyl genes provides valuable insight towards genetic engineering for the development of more potent industrial strain.