Abstract:
The aim of this work was to study the production of recombinant xylanase using a Kluyveromyces lactis
GG799 strain with a plasmid vector pKLAC1 carrying xylanase coding gene (XynA) isolated from Bacillus
pumilus MTCC 5015. To obtain maximum xylanase expression, statistical approaches based on response
surface methodology (RSM) was employed. Critical variables for recombinant xylanase production were
identified by one-variable-at- a- time approach followed by response surface methodology (RSM), which
led to an enhancement in extracellular xylanase production (200 IU/mL). Maximum xylanase production
was obtained when 2% of casamino acid was used along with 5% of galactose (inducer) with an inoculum
size of 2.75% (5×108 CFU/mL) when incubated for 48 h with a pre-inoculum age of 24 h (273 IU/mL). Thus,
a four-fold increase in activity from 70 IU/mL to 273 IU/mL could be achieved. SDS-PAGE analysis showed
that the relative molecular mass of glycosylated XynA was about 35.0 kDa. The partially purified enzyme
was used for the bio-bleaching of paper carton, which showed its effective application in bleaching
