Annuar, M.S.M.

Cheong, K.L.

Tan, I.K.P.

UM Digital Repository

12th Biological Sciences Graduate Congress17-19 December 2007University of MalayaI Tl-P14 IProduction of Medium-Chain-Length Polyhydroxyalkanoatesby Fed-Batch Fermentation, Using Oleic Acid asCarbon SourceK.L. Cheong, M.S.M. Annuar and I.K.P. TanInstitute of Biological Sciences, Faculty of Science, University of MalayaThe production of medium-chain-length polyhydroxyalkanoates (mcl-PHA) byPseudomonas putida PGA1 using palm oil and its derivatives as carbon substrateshad been established in this laboratory. PHAs are elastomers with low crystallinity,and they have attracted global interest as potential substitutes for petrochemicalplastics. Thus there is a requirement for higher quantities of this biopolymer forapplications evaluation. Scaling up studies was performed using 5 litre, 10 litreand 50 litre fermenters implementing a fed-batch system with oleic acid as thesole carbon source in mineral salts medium. Intermittent feeding of magnesiumsulfate solution minimizes the precipitation between the medium's mineralcomponents and oleic acid. The production of mcl-PHA was significantly improvedWhen double-limitations of nitrogen and phosphate elements were imposed onthe culture as compared to the single-limitation of either element. The 5Lfermentation runs had consistently generated about 40g/L total biomass (dryweight) of which 38% was mcl-PHA. By employing optimal feeding strategy andmaintaining dissolved oxygen at a constant level in the liquid medium, totalbiomass and mcl-PHA content obtained for the 10L fermentation runs averaged52 giL and 480/0, respectively. The 50L runs presented a classic case of scaling-up issue with mass transfer limitation; the total biomass yield was reduced to11 giL, nevertheless the mcl-PHA content remained significant at 48% of thetotal biomass.183

Production of medium-chain-length polyhydroxyalkanoates

by fed-batch fermentation, using oleic acid as carbon source

http://eprints.um.edu.my/14866/1/0001.pdf

Production of medium-chain-length polyhydroxyalkanoates by fed-batch fermentation, using oleic acid as carbon source

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