Production of Thermo-Alkali-Stable Xylanase from Bacillus licheniformis Isolated from Natural Hot Water Geyser

CONTEXT: Xylanase constitutes 20% of world enzyme market. Significantly, they are used in poultry feed, paper pulp, bakery, and textile industries. In view of the increasing demand of the enzyme, it is vital to develop indigenous strains and scalable technologies for the production of industrial enzymes. AIMS: The objective of the present paper was to isolate a high-yielding strain of thermo-alkali-stable xylanase-producing bacteria for potential application in paper and pulp and biofuel industry. METHODS: Sampling for prospecting of suitable organism was carried out from the places with dead and decaying lignocellulosic waste, and then Congo red screening was employed for the primary isolation of xylanase producers. RESULTS: We report the isolation of 18 different strains of xylanase producer bacteria from natural hot water geyser of Sohna, Haryana, India. Subsequently, two of these isolates were chosen for further studies based on xylanase yield and desirable properties such as thermostability and alkali stability of xylanase produced. CONCLUSION: Isolate B2 was later identified as Bacillus licheniformis, whereas isolate Y3 was identified as Brevibacillus borstelensis. This strain when cultured at 35°C for 72 h showed xylanase production at 128 U/ml. The molecular weight of xylanase was determined to be 25 kDa. The production was scaled up in a 5-L stirred-tank bioreactor which led to high xylanase concentration of 380 U/ml in the first 48 h of culture.