Processes for producing microbial copolyesters from sucrose-containing feedstocks

Abstract

A process for producing hydroxyalkanoate copolymers, which comprises: (i) pre-treating a sucrose-containing feedstock in an acidic solution; (ii) feeding the pre-treated feedstock into a bioreactor containing polyhydroxyalkanoate producing microbial cells; (iii) cultivating the polyhydroxyalkanoate producing microbial cells to form a cell mass containing the hydroxyalkanoate copolymers; (iv) recovering the hydroxyalkanoate copolymers from the cell mass. The pre-treating step has the main function of hydrolyzing sucrose into glucose and fructose, which in turn are converted into 4-ketovaleric acid to give a mixture of mono-saccharides and organic precursors for microbial synthesis of hydroxyalkanoate copolymers, and particularly of PHBVV ter-polymers. Complex and expensive purification processes of the substrates obtained from the pre-treating step are not needed. The solutions can be directly used as the feeding solutions for microbial PHA biosynthesis.