SYNTHESIS OF POLYHYDROXYBUTYRATE BY HERBASPIRILLUM SEROPEDICAE Z69 LAC+ USING WHEY PERMEATEA.I. CATALÁNA, C. CALLEJAS, G. MARTÍNEZ, H. VARELA AND S. BATISTAAbstract Whey permeate, a dairy industry byproduct, was used as carbon source and culture medium for poly-3-hydroxybutyrate (PHB) production by a Lac+ recombinant strain of Herbaspirillum seropedicae Z69. In flask experiments, utilization of whey permeate in LGI medium was evaluated for PHB production under nitrogen limitation. PHB content of 38.5% at 0.067gL-1h-1 was obtained for cells grown with 30.0gL-1 lactose in permeate. A feeding experiment was done using shaking flask cultures divided into three subcultures after 54h growth. The final PHB content obtained in the flask supplemented with permeate at 10.0gL-1 lactose and the one with permeate at 10.0gL-1 lactose and 10mM NH4Cl as final concentrations was 56.5 and 58.0%, respectively. Whey permeates as growth medium supplemented with NH4Cl was also used in a bioreactor. After 77h growth, biomass was 4.0gL-1 and PHB content 52.0%. Supplementation of LGI medium with permeate in bioreactor resulted in faster growth, with 6.0gL-1 biomass and 51.6% PHB content. This study provides a promising approach for production of polyhydroxyalkanoates by a H. seropedicae Lac+ recombinant strain using whey permeate as nutrient source for growth.
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