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Articles by Regina Vasconcellos Antonio
Total Records ( 3 ) for Regina Vasconcellos Antonio
  Gustavo Graciano Fonseca and Regina Vasconcellos Antonio
  Polyhydroxyalkanoates (PHAs) are thermoplastic, biodegradable polyesters, synthesized by some bacteria from renewable carbon sources. However, its application is limited by the high cost of production. To reduce these costs, recombinant strains that use diverse carbon sources have been developed. In this study, it was studied PHAs production by recombinant Escherichia coli (DH10B and JM10), harboring the structural genes of the polyhydroxyalkanoate synthases of Pseudomonas aeruginosa, using hydrolyzed corn starch and soybean oil as substrate, cheese whey as supplement and acrylic acid as fatty acids β-oxidation inhibitor. Their effect on the cell mass and the PHA content had been evaluated through an experimental design 24. The best results had been obtained with DH10B strain: Dry cell weight of 1.02 g L-1 and 23% of PHA (9 mol% 3-hydroxybutyrate, 4.5 mol% 3-hydroxyoctanoate, 30.7 mol% 3-hydroxydecanoate and 55.8 mol% 3-hydroxydodecanoate), in mineral media containing 5% of hydrolyzed corn starch, 5% de cheese whey and 5% of soybean oil, beyond 1 mM of acrylic acid.
  Gustavo Graciano Fonseca and Regina Vasconcellos Antonio
  Polyhydroxyalkanoates (PHAs) are thermoplastic, biodegradable polyesters, synthesized for some bacteria from renewable carbon sources. However, its application is limited by the high cost of production. To reduce these costs, recombinant strains that use diverse carbon sources have been developed. In this study, it was studied PHAs production by recombinant Escherichia coli (DH10B and JM10), harboring the structural genes of the polyhydroxyalkanoate synthases of Ralstonia eutropha and Pseudomonas aeruginosa, using hydrolyzed corn starch and soybean oil as substrate, cheese whey as supplement and acrylic acid as fatty acids β-oxidation inhibitor. The effect of these on the cell mass and the PHA content had been evaluated through an experimental design 24. The best results had been obtained with DH10B strain, with a dry cell weight of 0.92 g L-1 and 5.9% of PHA (0.5 mol% 3-hydroxybutyrate, 44.9 mol% 3-hydroxyhexanoate and 54.6 mol% 3-hydroxyoctanoate), in mineral media containing 5% of soybean oil, beyond 1 mmol of acrylic acid.
  Gustavo Graciano Fonseca and Regina Vasconcellos Antonio
  Polyhydroxyalkanoates (PHAs) are biodegradable, thermoplastic polyesters produced from renewable carbon sources by a number of bacteria. However, their application is limited by high production costs. One of the strategies aimed to reduce their costs is the development of recombinant strains able to utilize different carbon sources. The optimal conditions for 3-hydroxybutyrate (P[3HB]) production by the recombinant Escherichia coli strain JM101, harboring Ralstonia eutropha PHA biosynthesis genes, in a defined medium containing hydrolyzed corn starch and soybean oil as carbon sources and cheese whey as a supplement had been established earlier. In order to optimize PHA production, the present study investigated the influence of other variables, such as isopropyl-1-thio-β-D-galactopyranoside (IPTG) and acrylic acid addition, temperature, inoculum size and cultivation time, on dry cell weight (DCW) and PHA accumulation through a 25 factorial design. Statistical models suggested that quite good PHA production performances would be obtained in E. coli JM101 cultures grown in a medium lacking IPTG and acrylic acid with an inoculum size of 5% (v/v) and performed at 37°C for 96 h. Theoretically, about 3.5 g L-1 DCW and 75% PHA could be accumulated. Acrylic acid had a negative effect on DCW at its high level (1 mmol) and was unable to promote incorporation of medium-chain-length units into PHA polymers as expected. Remarkably, IPTG, a very expensive inducer of PHA synthesis gene expression had no influence on PHA production.
 
 
 
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