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Enhancing the 3‐hydroxyvalerate component in bioplastic PHBV production by Cupriavidus necator
Author(s) -
Berezithalie
Publication year - 2012
Publication title -
biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.144
H-Index - 84
eISSN - 1860-7314
pISSN - 1860-6768
DOI - 10.1002/biot.201100191
Subject(s) - cupriavidus necator , bioplastic , polyhydroxyalkanoates , component (thermodynamics) , production (economics) , chemistry , food science , bacteria , biology , waste management , physics , engineering , genetics , thermodynamics , macroeconomics , economics
In the current context of global warming, the substitution of conventional plastics with bioplastics is a challenge. To take up this challenge, we must meet different technical and economic constraints. In the case of poly(3‐hydroxybutyrate‐ co ‐3‐hydroxyvalerate) (PHBV), the technical properties can be modulated by varying the 3‐hydroxyvalerate content. 3‐Hydroxyvalerate (3‐HV) enhancement is an issue; therefore, simultaneous evaluation of several 3‐hydroxyvalerate‐enhancing substrates through fractional factorial design of experiments is described. Eight substrates citric, valeric, propionic, and levulinic acids; propanol; pentanol; and sodium propionate were studied for 3‐HV enhancement, and sodium glutamate was studied for biomass and polyhydroxyalkanoate (PHA) enhancement. The most efficient 3‐hydroxyvalerate‐enhancing factors were levulinic acid, sodium propionate, and pentanol; however, pentanol, at a concentration of 1 g/L, had an extremely negative influence on biomass production and the PHA content of cells. The effect of the inoculum nutrient composition on the final 3‐HVcontent was also evaluated. These results showed that the most efficient combination for the production of high 3‐HVcontent in PHBV was primary inoculum growth on mineral medium followed by fermentation for 48 h with levulinic acid and sodium propionate (at 1 g/L) as the only carbon sources. This allowed us to produce PHBV with a 3‐HVcontent of 80 mol % and overall volumetric and specific productivities of 2 mg/L/h and 3.9 mg/g CDW /h, respectively, with the addition of only 2 g/L of inducing substances.