High yield production of the latex clearing protein from Gordonia polyisoprenivorans VH2 in fed batch fermentations using a recombinant strain of Escherichia coli.

The enzymatic degradation of rubber with the latex clearing protein (Lcp1VH2) from Gordonia polyisoprenivorans VH2, is a promising option as an environmentally friendly and economical solution to treat the enormous amount of rubber waste. Here we present a fed batch fermentation process on a 10 L scale, using E.coli C41 pET23a(+)::Hislcp1VH2 and a modified defined mineral salt medium, designed for high cell densities, for a proper synthesis of Lcp1VH2. Particularly, providing complex media components, as well as hemin, as precursor of the essential heme b cofactor, resulted in a 2.9-fold higher yield of active Lcp1VH2 with increased specific activity, due to a better occupancy of the enzyme with the cofactor. Based on this optimization, the fed batch fermentation with an initial glucose feed, followed by a lactose-glycerol feed, finally gained a cell dry weight of 60 g L-1 and a yield of 223 mg L-1 of soluble, active Lcp1VH2. Compared to a recently published fermentation process, which used a complex auto-induction medium, we significantly increased the biomass up to nearly 10-fold and the total Lcp1VH2 yield up to 3.7-fold. Thereby we reduced the costs for the medium by 75 %, taking the next step towards industrial production of rubber degrading enzymes.