Bt Research 2015, Vol.6, No.3, 1-10
9
measured by standard assay procedure and compared
with the control. To inactivate the enzyme in the
commercial detergent, aqueous solution of detergent
was initially heated at 100
℃
for 60 min. The
reaction conditions for the protease from
Btk
were: 15
mg/ml casein as substrate for 30 min at pH 9 and
70
℃
(
i.e
., the optimized condition), and 0.7%
inactivated detergent (to stimulate washing condition).
Statistics
For accuracy, all experiments were repeated 3 times.
Microsoft Excel 2007 was used for calculating the
protease activity and standard error. Adobe Photoshop
CS Version 8 was used to set the figures. The
Km
and
Vmax
values were calculated using the effect of casein
on enzyme activity using the software Hyper 32 and
Graph pad prism.
Conclusions
Proteases associated with toxicity are reported from
Bt
by various authors; but this is the first report on a
protease from
Bt
showing its utility in industry.
Normally, the supernatant in the culture medium is
discarded after extracting the
δ
-endotoxin and endospore.
By this biphasic fermentation strategy, the supernatant
in the medium was collected during the early phase of
the growth of
Btk
, from which the protease was
purified. Removal of free solution from the medium
not only enhanced the production of
δ
-endotoxin as
already demonstrated, but the harvest of valuable
protease as by-product as well.
Author’s Contribitions
SB designed and prepared the manuscript, VNJ did the
experiments, SS and PP set the reference and figures, RBS
collected the literature.
Acknowledgements
JVN is grateful to the University Grants Commission,
Government of India for granting Rajiv Gandhi National Research
Fellowship. The support rendered by National Institute of
Technology, Calicut for taking the SEM images is thankfully
acknowledged.
Conflict of Interest
The authors declare that there exist no competing financial or
other interests.
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