Polyunsaturated Fatty Acids (Pufas) Of Mucor Sp. With Special Reference To Gamma Linolenic Acid (Gla)
IR@CFTRI: CSIR-Central Food Technological Research Institute, Mysore
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http://ir.cftri.com/9949/
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Title |
Polyunsaturated Fatty Acids
(Pufas) Of Mucor Sp. With Special
Reference To Gamma Linolenic
Acid (Gla)
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Creator |
Mamatha, S. S.
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Subject |
19 Lipids-oils/fats
04 Microbiology |
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Description |
Lipids are one of the main classes of macronutrients required for human
growth and nourishment. In order to obtain native isolate for GLA production, soil
samples were collected from various habitats for screening the Mucor spp. in
nutrient rich medium. Based on the external morphology and microscopic
observation Mucor spp. were isolated, compared with the standard cultures and
comparisons were also made with the Gilman manual of soil fungi
These isolates were screened for their oleagenicity both qualitatively and
quantitatively, staining with Sudan black-B and gravimetric method respectively.
All the selected Mucor spp. and standard cultures were cultivated on submerged
fermentation to study the growth characteristics, lipid and GLA contents. The
results indicated that the highest biomass, lipid and GLA content were observed in
M. rouxii CFR-G15. The presence of GLA in the lipid of this isolate was
confirmed by the mass spectrometric method.
By using gene specific primers, 18S rRNA and D6 DES genes were amplified
by PCR technique. Nucleotide sequences of 18S rRNA and D6 DES genes
exhibited 98% homology with M. rouxii ATCC 24905 (accession no.AF117923
and AF296076) respectively, suggesting taxonomic identity. A nucleotide
sequences determined in this study was submitted to the GenBank and obtained
the accession numbers EU927296 and EU526025 for 18SrRNA and D6 DES genes
respectively.
Cultivation conditions were selected for GLA production by optimizing
appropriate selection of both physical and chemical parameters such as pH,
temperature, aeration, inoculum concentration, medium composition, carbon and
nitrogen sources, C:N ratio combination, different vegetable oils, and different
concentration of minerals in growth media. It was concluded in this study that pH
5.5, temperature at 28±2°C, glucose, yeast extract & ammonium nitrate as carbon
and nitrogen sources and C:N ratio of 60 produced maximum biomass, lipid
production and GLA content in this strain. A CCR design was used for
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optimizing the levels of carbon and nitrogen sources to maximize the GLA
production by RSM. By using different solvent extraction, this study concluded
that chloroform and methanol in 2:1 ratio gave maximum recovery of lipid.
The M. rouxii CFR-G15 was subjected to mutation through physical and
chemical methods (UV, EMS & NTG) and after several screening, a metauxotroph
was obtained and this amino acid marker was used for hybridization
studies to obtain stable hybrids. Putative hybrids were qualitatively characterized
for high lipid and GLA production. Hybrid CFR-HyG 9 showed highest GLA
content of 23.34 ±1.23 % in 42.46±2.41% of lipid content which was 1.5 fold
higher than the parent culture in basal medium. Thus, the various experiments
carried out in this study, ultimately aimed to increase the biomass, total lipid
content and maximizing the GLA production.
Plants beings the conventional sources of essential fatty acids have some
limitations/disadvantages that can be over ruled by microorganisms. Hence
microorganisms of GRAS status are now being exploited genetically as sources of
PUFAs and tailored for maximum productivity. The potential also exists in
selecting the microbial strains producing large proportions of lipid that can meet
the present market demand of omega-6 fatty acids, the GLA for nutritional and
pharmaceutical supplementation.
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Contributor |
Venkateswaran, G.
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Date |
2009-11
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Type |
Thesis
NonPeerReviewed |
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Format |
application/pdf
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Language |
en
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Rights |
—
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Identifier |
http://ir.cftri.com/9949/1/Mamatha_S_S_Thesis_Final.pdf
Mamatha, S. S. (2009) Polyunsaturated Fatty Acids (Pufas) Of Mucor Sp. With Special Reference To Gamma Linolenic Acid (Gla). PhD thesis, University of Mysore. |
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