I= FERMENTATION PATTERN OF FUNGAL LIPASES AND THEIR APPLICATION FOR ESTERIFICATION IN NON-AQUEOUS MEDIA
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Title of Thesis
FERMENTATION PATTERN OF FUNGAL LIPASES AND THEIR APPLICATION FOR ESTERIFICATION IN NON-AQUEOUS MEDIA

Author(s)
Ahmad Adnan
Institute/University/Department Details
Institute of Chemistry/ University of the Punjab
Session
1998
Subject
Chemistry
Number of Pages
230
Keywords (Extracted from title, table of contents and abstract of thesis)
fermentation, fungal lipases, esterification, non-aqueous media, lipolytic microorganisms, rhizopus arrhizus, flavouring esters, fusel oil

Abstract
Lipolytic fungi we isolated from the soil and food samples using a selective isolation medium. The isolated fungal cultures were screened for found to produce maximum lipase. The fungus Rhizopus arrhizus (isolate: 52) was found to produce maximum lipase. The fermentation medium M5, consisting of (g/dm3):- olive oil, 20; yeast extract 1.0; magnesium sulphate heptahydrate 0.25; calcium carbonate, 5.0 was found to be the best medium for lipase formation by Rhizopus arrhizus. The cultural conditions like medium composition, pH, aeration rate and incubation temperature were optimized for the production of the intracellular lipase by Rhizopus arrhizus in sake flasks. The optimization of the fermentation conditions resulted in about three fold increase in the production of lipases. This optimized medium gave 13.5 g/dm3 fungal biomass with 325 lipase units/g dry mycelium and bout 2.4 units extracellular lipase per cm3 of the broth. The fermentation was also carried out in 18 dm3 stirred fermenter and 4 dm3 airlift production. The airlift fermenter was found to be especially suitable for the intracellular lipase production. In it, the fungus Rhizopus arrhizus produced 375 units lipase per gram mycelium and 14.2 g mycelium per dm3 medium. In stirred fermenter,, however, both fungal biomass and intracellular lipase activity were comparatively low.

Rhizopus arrhizus was also cultured in solid substrate fro extracellular lipase production. Different agricultural by products such as wheat bran, gram bran, rice husk, soybean meal and rice bran were evaluated for lipase production. A mixture of wheat bran and soybean meal, however, was found to be the best substrate. Additives like olive oil and the egg yolk emulsion increased lipase production.

The extracellular and intracellular lipase of the mould Rhizopus arrhizus were used for the biocatalysis of esterification reactions. Free excellular lipase showed very low esterification activity (28 esterification units/g) whereas the celite immobilized lipase catalyzed synthesis of hexyl octanoate at the rate of 51 micromoloe/min/gram. Mycelial lipase of Rhizopus arrhizus, however, was very active in organic media and performed the synthetic work efficiently. In n-hexane, at 30oC the mycelial lipase of Rhizopus arrhizus Catalyzed the synthesis of hexyl octanoate at a rate of 92 micromoles/min/gram mycelium.

The mycelial lipase of Rhizopus arrhizus was also used for the production of fragrant esters from the fusel oil and terpene alcohols. Geranyl butyrate and butyrate of fusel oil were manufactured using a packed column reactor. In case of the fusel oil, ester yield of 87% was obtained by recycling the reaction mixture through the column for 3 times. In case of esterification of geraniol with butyric acid, the esterification yield was 77%

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S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
228.71 KB
2 1 Introduction 1-8
74.12 KB
3 2 Literature Review 8
458.68 KB
  2.1 Enzyme Sources 8
  2.2 Isolation And Maintenance Of Lipolytic Microorganisms 9
  2.3 Production Of Microbial Lipases 10
  2.4 Lipase Mediated Ester Synthesis 22
4 3 Methodology 37
181.89 KB
  3.1 Lipase Production 37
  3.2 Esterification Reactions 46
  3.3 Analysis 47
5 4 Results And Discussion 53
1129.47 KB
  4.1 Isolations, Screening And Selection 53
  4.2 Lipase Production Submerged Fermentation By Rhizopus Arrhizus 62
  4.3 Solid Substrate Fermentation 106
  4.4 Partial Purification And Immobilization Of The Extracellular Lipase 121
  4.5 Lipase Catalyzed Ester Synthesis 125
  4.6 Production Of Flavouring Esters From Fusel Oil 146
  4.7 Terpene Ester Synthesis 158
6 5 References 162-207
649.9 KB