A novel approach in lactose based induction for enhanced production of 1-4-beta xylanase by recombinant Escherichia coli

Escherichia coli BL21 (DE3) with a plasmid vector pET-22b (+) carrying xylanase coding gene isolated from an extremely thermophilic bacterium, Thermotoga sp. was used in this work for enhanced production of recombinant xylanase. The study was focused on optimization of lactose based induction for enhanced production of xylanase. Data collected from OFAT and DoE based trails indicated that initiation of lactose based induction at the very early phase of cell growth in maltose base media enhances xylanase production significantly. During further induction strategy optimization trails, intracellular xylanase production was enhanced up to 2600 IU mL-1 when the expression was induced by 8 gL-1 of lactose at early log phase (between 2-4 hours) of the cell growth. From induction temperature optimization trials, it was found that xylanase production can be further enhanced by reducing the incubation temperature from 37 to 32ºC. Using the optimum induction strategy developed, up to 6430 IU mL-1 xylanase activity was achieved. This value was almost 3 folds higher than those obtained in IPTG induced cultures