Optimization of procedural factors for advanced xylanase synthesis by Lysinibacillus fusiformis using Kolanut husk as substrate

Abstract

Xylan is a complex hetero-polysaccharide consisting of different monosaccharides held together by glycosidic and ester bonds. Extracellular xylanase fashioned by numerous microbes principally from bacterial species such as Bacillus species are responsible for cleaving the glycosidic linkages. Microbial xylanases exhibit different substrate specificities and biochemical peculiarities. This study was carried out for optimization of cultivation conditions for xylanase production using the bacterium Lysinibacillus fusiformis and Kolanut husk as a component of cultivation medium. The bacterium was isolated from Kolanut plantation waste soil and screened for the production of xylanase qualitatively on xylan nutrient agar and quantitatively under submerged fermentation. The different conditions optimized included substrate concentration, additional sugars, incubation period, temperature, initial pH, nitrogen supplementation and inoculum mass through one factor at a time approach. Maximum xylanase production was obtained at substrate concentration of (1 % xylan and 1.5 % Kolanut husk), nitrogen source (yeast extract plus peptone), carbon source (sucrose), incubation period (24 h), pH (5.0), temperature (35 oC) and inoculum size (1 %). Lysinibacillus fusiformis has been proven to be a promising bacterium for xylanase production using Kolanut husk as substrate. The use of Kolanut husk as foremost carbon source is predominantly precious as being an agricultural waste, affordable, and locally available compared to expensive commercially sold xylan.