ANNUAL REPORT - Department of Biotechnology

vegetable waste were found to be suitable as feed
stock for bioethanol production. Cost economics of
bioethanol production is being worked out at pilot
scale.Thermotolerant yeast strain (Saccharomyces
cerevisiae) identified, characterized and studies
towards complete utilization of starch for ethanol
production were carried out. In a study supported at
University of Delhi South Campus, New Delhi,
methodology has been developed for chemical
hydrolysis of lignocellulosic wastes like Lantana
camara and Prosopis juliflora into fermentable
sugars and subsequent conversion into ethanol will
be refined. The lignin degrading fungal isolate are
being characterized. Recombinant microbial strains
have been identified, which show enhanced ethanol
recovery.
In an ongoing project on bioethanol production at
Osmania University, Hyderabad, efficient cellulose
producing microorganisms have been identified.
Pentose utilizing fusant has been constructed by
protoplast fusion between thermotolerant yeast and
Candida utilis. Fusant strain has been sent to
IMTECH, Chandigarh for molecular
characterization. Cloning, expression and
confirmation studies are in progress. Ethanol
fermentation upto 20 litre level was carried out.
Further optimization work is going on.
Cyanobacterial strain, Phormidum sp. BDU-5 has
also been used for degradation of different cellulosic
wastes like P. julflora, L. camara and coir pith. By
products released during degradation are being
studied. Besides, phenolic compounds like 3, 4dimethoxy
cinnamic have been isolated and furher
purification is being carried out by solvent extraction
and column chromatography.
The substrates were delignified and hydrolysed to
obtain fermentable sugars using Candida shehatae,
Pichia stipitis and co-culture of both. In a12 L batch
fermentor, Candida shehatae maximum ethanol
yield was 18.78 g/L (0.65 g/g), followed by 16.72 g/L
(0.62 g/g) by P. stiplis and 12.48 g/L (0.48 g/g) in coculture
after 36 hrs. The optimization of enzymatic
saccharification has been carried out and is further
being optimized, before economic evaluation is
done.
Based on discussion with experts future priorities
under bioethnaol programme have been identified.
These include development of a low cost cellulose /
hemi cellulose for enzymatic hydrolysis which could
be achieved either through natural selection of
microorganism or development of a recombinant
microorganism(s) or microbial consortia. Studies
would also be initiated to develop an efficient
process for production/scale up of the enzyme either
through solid state or submerged fermentation.
Simultaneous fermentation of both pentose and
hexose for ethanol production either through
development of recombinant microorganisms or
coculture would also be taken up. Impetus will be on
development of an efficient biological pre-treatment
system for delignification.
Hydrogen from Biomass
Various efforts have been made to explore
production of biological hydrogen from available
biomass sources. In a study supported at
Bharathidasan University, Trichirappalli, marine
cyanobacteria have been screened for hydrogen
photoproduction both in argon and nitrogen
atmospheres under light regimes. All nonheterocystous
filamentous strains tested produced
hydrogen in nitrogen atmosphere with slight
reduction. Production of hydrogen in nitrogen
atmosphere finding totally disproves the earlier
findings that hydrogen could not be produced in
nitrogen atmosphere. By methane supplementation
(5% - 20%) in nitrogen atmosphere the reduction of
hydrogen rate could be revoked. Besides, a survey
was carried out along the coast from Mimesal to
Mandapam and Rameswaram and Kurusadai
islands for marine photosynthetic bacterial
collection. The survey yielded more than 50 different
isolates of different groups of photosynthetic
bacteria. This would be helpful in designing the
integrated bioreactors for hydrogen photoproduction
and the work in this direction is going on.
131 Research and Development