Production of XXXX by Halomonas boliviensis in an air-lift reactor.

@entity6122 @entity3505 @entity13099 @entity7969 @entity16749 @entity13100 @entity1110 @entity9931 @entity505 @entity413 @entity36435 @entity2635 @entity3363 @entity526
BACKGROUND: Microbial polyesters, also known as polyhydroxyalkanoates (PHAs), closely resemble physical and mechanical features of petroleum derived plastics. Recombinant @entity526 strains are being used in industrial production of PHAs in Stirred Tank Bioreactors (STRs). However, use of Air-Lift Reactors (ALRs) has been known to offer numerous technical operating options over STRs, and as such has been successfully implemented in many bioprocesses. Halomonas boliviensis is a halophilic bacterium that is known to assimilate various @entity3363 and convert them into a particular type of PHA known as @entity13099 ( @entity13100 ). Owing to this capability, it has been used to synthesize the @entity2635 using hydrolysates of starch or @entity3505 bran in stirred tank bioreactors. RESULTS: This research article firstly describes the production of @entity13100 in shake flasks by H. boliviensis using different combinations of @entity3363 and partially hydrolyzed starch as @entity505 sources. The highest @entity13100 yields, between 56 and 61  % (wt.), were achieved when either starch hydrolysate or a mixture of @entity413 and @entity6122 were used as @entity505 sources. The starch hydrolysate obtained in this study was then used as @entity505 source in an ALR. The largest amount of @entity13100 , 41  % (wt.), was attained after 24  hrs of cultivation during which @entity7969 in the hydrolysate was assimilated more rapidly than @entity413 during active cell growth; however, the rate of assimilation of both the @entity3363 was found to be similar during synthesis of @entity13100 . An incomplete @entity36435 pathway, which lacks @entity16749 dehydrogenase, was deduced from the genome sequence of this bacterium and may result in the characteristic assimilation of @entity413 and @entity7969 by the cells. CONCLUSIONS: This study showed that the production of @entity13100 by H. boliviensis using cheap substrates such as starch hydrolysate in a simple production system involving an ALR is feasible. Both @entity7969 and @entity413 in the hydrolysate induce cell growth and @entity13100 synthesis; most likely the cells balance adequately @entity9931 and @entity1110 during the assimilation of these @entity3363 . The combination of cheap substrates, simple production systems and the use of non-strict sterile conditions by the halophile H. boliviensis are desirable traits for large scale production of @entity13100 , and should lead to a competitive bioprocess.
