ANNUAL REPORT - Department of Biotechnology

ecorded 50 times batch run without any loss of
efficiency of conversion rate.
In another study, potential of black tea and its
constituents in reversal of multidrug resistance and
as bio-enhancer are being studied. The non-toxic
concentrations of tea polyphenols were found to
effectively reverse the drug resistance as evident by
p-glycoprotein expression (through western blotting)
and increased drug uptake of doxorubicin (through
flow cytometry). Potential of tea polyphenols as bioenhancer
in cancer chemoprevention studies,
experiments on hepato-carcinogenesis and skin
carcinogenesis were undertaken revealed that
polyphenolic constituents of both varieties of tea,
green and black are providing significant protection
against cancer induction in vivo models.
c) Enhanced Omega-3 fatty acid content in
foods: Alpha linolenic acid (ALA) is an essential
omega-3 fatty acid required in the diet that gets
converted in the body to Eicosapentaenoic acid and
Docosahexaenoic acid that form precursors
respectively for eicosanoids and membrane
components especially, brain and retina. Many
microorganisms can desaturate the abundant plant
linoleic acid (LA) to ALA that is poorly present in plant
oils. Work to develop recombinant yeast strains
capable of converting LA to ALA extracellularly was
carried out. More than 100 yeast isolates were
collected, mostly from the premises of plant oil mills
from different parts of the country, and grouped into
forty independent types based on colony and cellular
characteristics. Genomic DNA was isolated from the
forty different strains and used for screening of
omega-3 desaturase gene by PCR. Primers were
designed based on sequence homology of a
published yeast omega-3 desaturase with those
present in algae, fungi and plants. When compared
across different phylogenetic groups there is over all
poor sequence similarity (23%-29%), with the
exception of cyanobacetria and Arabidopsis which
showed 45%-50% similarity. Three aminoacid
clusters, 16-22 aa long with 45%-50% similarity
among all the known desatuarse, was used for
designing primers. Seven out of forty samples
yielded ~600 bp amplicon. These were further
confirmed by PCR using a different set of primers
and 2 DNA hybridization studies. The PCR positive
strains were able convert LA to ALA.
d) Beta-carotene from Alga: A total of 272 salt
pans seawater samples were collected along the
coasts of Andhra Pradesh and Tamil Nadu. Most of
the samples contained the quadriflagellate alga like
Tetraselmis. Only a few samples known to contain a
mixture of naked green algal species Dunaliella, thus
indicating the rare occurrence of the species. The
algal colonies appeared after 20 days were isolated
and maintained. Dunaliella strains were investigated
for their growth study and total carotenoids and
potential strains have been identified for enhanced
beta carotene production. In another study,
carotenoids and fatty acid composition of some
selected Indian brown and red seaweeds were
analysed and phenolic content and antioxidant
activity of extracts from seaweeds were also
analysed. The brown seaweeds analysed included
Sargassum marginatum, Padina tetrastromatic and
Turbinaria connoides; while, the red seaweeds
included Acanthophora spicifera, Euchema
kappaphycus and Gracilaria folifera. The lipid
content in various seaweeds varied between 1.0 and
3.0% (dwb) with P. tetrasromatica showing the
highest content. Glycolipids were found to be a major
lipid class, followed by neutral and phospholipids, in
brown as well as red seaweeds. Brown seaweeds
were found to contain fucoxanthin as the major
pigment. Fucoxanthin content of fraction obtained by
column chromatography was found to be >90%.
Among the various solvent fractions obtained,
butanolic fraction of E. kappaphycus was found to
contain the highest. The red seaweeds showed
relatively higher antioxidant activity than brown
seaweeds as indicated by radical scavenging
activity.
e) Microbial Production of Nicotinamide:
Nicotinamide is one of the important vitamins B3, which is mainly used in pellagra and niacin
deficiency. It also has an antioxidant and
cytoprotective effect. The other form of vitamin B3 is
nicotinic acid, which is equally important as
nicotinamide. In this project a large number of
microbes have been screened for both nicotinamide
and nicotinic acid production. The nitrile hydratase
activity of these strains was determined by assaying
the enzyme activity. The HPLC method was
developed to determine 3-cyanopyridine,
nicotinamide and nicotinic acid. Good nitrile
145 Bioprocess and Product Development