Phototrophic Growth and Accumulation of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)‎ by Purple Nonsulfur Bacterium Rhodopseudomonas palustris SP5212

Abstract EN

The ability of the phototrophic bacterium Rhodopseudomonas palustris SP5212 to produce polyhydroxyalkanoates (PHAs), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] in particular was, assessed in acetate medium supplemented with hydroxybutyrate and valerate as cosubstrates.

The isolate accumulated the polymer accounting for some 49.06% and 30% of cell dry weight when grown in hydroxybutyrate and valerate, respectively.

PHA accumulation as well as 3HV monomer incorporation (30 mol%) was maximum at 0.1% hydroxybutyrate, while valerate at 0.1% and 0.3% was suitable for total polymer accumulation and 3HV monomer incorporation, respectively.

Cosupplementation of hydroxybutyrate and valerate in the ratio of 3 : 1 led to the accumulation of PHA accounting for 54% of cell dry weight, which contained more than 50 mol% of 3HV monomer.

Moreover, the biphasic cultivation conditions with hydroxybutyrate as cosubstrate have improved the quality as well as quantity of the accumulated copolymer significantly.