Authors: T M Fahima Azira A A Nursolehah Y Norhayati M I A Majid A A Amirul
Publish Date: 2011/02/23
Volume: 27, Issue: 10, Pages: 2287-2295
Abstract
A locally isolated Gramnegative bacterium Cupriavidus sp USMAA24 was found capable of producing terpolymer poly3hydroxybutyrateco3hydroxyvalerateco4hydroxybutyrate P3HBco3HVco4HB using γbutyrolactone or 14butanediol with either valeric acid or 1pentanol as the carbon source The present of 3HB 3HV and 4HB monomers were confirmed by gas chromatography GC and nuclear magnetic resonance NMR analysis PHA concentration of 19 g/l was the highest value obtained using the combination of 14butanediol and 1pentanol through onestep cultivation process PHA concentration obtained through twostep cultivation process was higher for all the combinations and the highest value achieved was 25 g/l using γbutyrolactone and 1pentanol as carbon source Various molar fractions of 4HB and 3HV ranging from 6 to 14 mol and 39 to 87 mol respectively were produced through twostep cultivation process by manipulating the concentration of γbutyrolactone As the culture aeration was reduced the molar fraction of 3HV and 4HB increased from 40 to 67 mol and 10 to 24 mol respectively while the dry cell weight and PHA content decreased The terpolymer produced was characterized using gel permeation chromatography GPC and differential scanning calorimetry DSC The numberaverage molecular weight M n and the melting temperature T m of the terpolymer were in the range of 177–484 kDa and 160–164°C respectively
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