Studies on polyhydroxyalkanoate (PHA) accumulation in a PHA synthase I-negative mutant of Burkholderia cepacia generated by homogenotization.
In the genome of Burkholderia cepacia strain IPT64, which accumulates a blend of the two homopolyesters poly(3-hydroxybutyrate), poly(3HB), and poly(3-hydroxy-4-pentenoic acid), poly(3H4PE), from sucrose or gluconate as single carbon source, the polyhydroxyalkanoate (PHA) synthase structural gene was disrupted by the insertion of a chloramphenicol-resistant gene cassette (phaC1::Cm). The suicide vector pSUP202 harboring phaC1::Cm was transferred to B. cepacia by conjugation. The inactivated gene was integrated into the chromosome of B. cepacia by homologous recombination. This mutant and also 15 N-methyl-N'-nitrosoguanidine (NMG)-induced mutants still accumulated low amounts of PHAs and expressed low PHA synthase activity. The analysis of the mutant phaC1::Cm showed that it accumulated about 1% of PHA consisting of 68.2 mol% 3HB and 31.8 mol% 3H4PE from gluconate. The wild-type, in contrast, accumulated 49.3% of PHA consisting of 96.5 mol% 3HB and 3. 5 mol% 3H4PE. Our results indicated that the genome of B. cepacia possesses at least two PHA synthase genes, which probably have different substrate specificities.
de Andrade Rodrigues
M F
MF
Instituto de Pesquisas Tecnológicas do Estado de São Paulo, Brazil.
Vicente
E J
EJ
Steinbüchel
A
A
D020155:3-Hydroxybutyric Acid / Q000378:metabolism; D000217:Acyltransferases / Q000235:genetics* / Q000378:metabolism; D015139:Blotting, Southern; D016956:Burkholderia cepacia / Q000235:genetics* / Q000378:metabolism*; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D006885:Hydroxybutyrates / Q000378:metabolism; D009154:Mutation; D010421:Pentanoic Acids / Q000378:metabolism; D011091:Polyesters / Q000378:metabolism*; D011995:Recombination, Genetic; D013379:Substrate Specificity; D014631:Valerates / Q000378:metabolism; D000094122:Polyhydroxybutyrates
D020155:3-Hydroxybutyric Acid; D000217:Acyltransferases; D006885:Hydroxybutyrates; D010421:Pentanoic Acids; D011091:Polyesters; D014631:Valerates; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates; C080194:3-hydroxy-4-pentenoic acid; C073314:poly(3-hydroxyvalerate); C077225:poly(3-hydroxyalkanoic acid) synthase