ANNUAL REPORT - Department of Biotechnology

study at Osmania University and IICT, Hyderabad,
corncobs recorded the highest xylose production
than other agro-products and 81g/kg xylose is
released from corncobs at optimum conditions.
Optimization studies are ongoing. Since sugarcane
bagasse was also used for the generation of
electricity, the commercial value of the bagasse has
increased. As H SO gave better xylose (0.2g/g) than
2 4
HCL (0.14g/g), H SO was selected for the acid
2 4
hydrolysis. Adaptation of Candida tropicalis to
corncobs hydrolysate for 18 cycles gave 52%
conversion of xylose to xylitol.
At JNU, New Delhi, investigations are being
conducted to study two major problems in host cell
productivity during high cell density cultivation of
recombinant E. coli viz., acetate accumulation and
oxygen starvation, by genetically modifying the host
cell machinery by introducing genes for Vhb and
pyruvate carboxylase. A reverse metabolic
engineering approach is also being used where a
library is being screened to identify metabolic blocks,
which might be beneficial to recombinant protein
expression.
In a study supported at CSMCRI, Gujarat,
functionalized chitosans and poly vinyl alcohol (PVA)
based nanoporous charged membranes were
prepared in the aqueous media and gelated in
0
methanol at 10 C for tailoring their pore structure.
These membranes were extensively characterized
for their physicochemical, electrochemical and
permeation characteristics using FTIR, TGA, DSC,
water content, ion-exchange capacity, ionic transport
properties and membrane permeability studies. Nmethylene
phosphonic chitosan (NMPC)/PVA based
membranes exhibited mild cation selectivity,
quaternized chitosan (QC)/PVA composite
membranes resulted mild anion selectivity while
blend of NMPC-QC/PVA membranes exhibited weak
cation selectivity because of formation of zwitterionic
structure. Elaborate electrochemical and
permeation experiments were conducted to predict
suitability of these membranes for the separation of
mono- and bi-valent electrolytes based on their
hydrated ionic radius and it was found that among all
the synthesized membranes PC/QC-30 was resulted
highest relative permeability, which may extend its
suitability for the electrolyte separations. The
feasibility of separation of BSA and lysozyme mixture
DBT Annual Report 2006-07
150
at desired pH and experimental conditions were
studied.
Environmental Application Products
At Jai Research foundation, Gujarat, a large scale
screening for the isolation of Bacillus thuringenesis
was undertaken to characterize the crystal protein
toxin genes (cry) available in Indian environment.
Several isolates harboring Lepidoptera and
Coleptera specific toxin genes were isolated and the
distribution of these toxin genes in the naturally
occurring system was unravelled. Efforts are being
done to characterize these isolates to exploit its toxin
potential to use in Indian agriculture for developing
insect resistance transgenic plants.
At CFTRI, Mysore, DDT dehydrohalogenase has
been identified as the potent enzyme for degradation
of DDT. This enzyme is responsible for the initial
dechlorination of DDT and is assayed in individual
bacterial isolates and also in the consortium. Dot blot
assay with AgNO 3 gave good response with bacterial
cell consortium for the presence or absence of DDT.
Generation of antibodies against DDT for biosensor
application is being done in poultry and rabbits.
Hyper expression of the DDT degradative genes in
suitable hosts for enzyme production is in progress.
At IIT, Delhi, protective properties of selected natural
dyes and chitosan derivatives for development of
multifunctional textiles are being investigated.
Treatment with modified chitosan makes it possible
to dye cotton in bright shades with cationic dyes
having high wash fastness. Results revealed that
treated cotton has better dyeability with direct and
reactive dyes and improved wrinkle recovery and
high antimicrobial activity against E. coli and S.
aureus and the effect was found to be durable for five
laundering cycles. Studies on the UV absorption
spectra of seven natural dyes showed that some of
these dyes could be used to produce cotton and
polyester fabrics offering high UV protection . The
UPF appears to be closely related to the fibre
properties and the dye fibre interactions and the
same dyes can give very different results on different
fibres. Terminalia chebula and Punica granatum
showed good results on cotton fabric.
At Delhi University, in an ongoing project on