Biosynthesis of Medium-chain-length PHA by Pseudomonas oleovorans
Date Issued
2007
Date
2007
Author(s)
Chou, Chi-En
DOI
zh-TW
Abstract
Biosynthesis of biodegradable PHA (polyhydroxyalkanoate) using Pseudomonas oleovorans was investigated. By using this microorganism, mclPHA can be synthesized. Comparing with sclPHA, the property of mclPHA is more flexible. To date only sclPHA have been synthesized at larger scale. Because of limited availability of the mclPHA, there are only a few reports on it.
Different products of PHA were obtained by using different carbon sources. When using sodium octanoate as a sole carbon source, major product was PHO (poly(3-hydroxyoctanoate)). Dissolved oxygen increases with higher stirrer speed, which promote metabolism of microorganism, logarithmic curve will end earlier. Change cultivation time from 30℃ to 18℃ at 8 hr can obtain 4.43g biomass/L, although dry cell weight was increased by a little, PHA accumulation was still too low. With fed-batch cultivation, PHA productivity is much lower than batch culture.
When feeding with undecylenic acid by flask culture, weight of PHA and PHA content were 2.148 g/L, 51.8% respectively. When feeding with undecylenic acid by fed-batch culture, there was a lag time when microorganism using undecylenic acid as a new carbon source. The molar fraction of unsaturated monomer could be achieved by 37.39% at 73 hr cultivation. We can see the property of PHA become flexible with cultivation time by the lower of Tg.
Subjects
聚羥基烷酯
Pseudomonas oleovorans
批次饋料
Polyhroxyalkanoates
mclPHA
fed-batch culture
Type
thesis
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