Saccharification of tomato pomace for the production of biomass

Several cellulase titers were used to saccharify suspensions of tomato pomace in 300 ml shake-flasks. The sacharification of the substrate produced glucose at different initial rates from 1.8 g of reducing sugar kg−1 per enzyme unit (at 10 g of tomato pomace kg−1) to 36.1 g of reducing sugar kg−1 per enzyme unit (at 160 g of tomato pomace kg−1). Maximum concentrations of reducing sugars were observed in the experiments with 160 g of tomato pomace kg−1 producing hydrolysates containing 49.7 g of reducing sugars kg−1. The maximum yield was 31% (w/w) corresponding to a 76% (w/w) cellulose conversion. The saccharification of tomato pomace also yielded other monosaccharides with the following distribution: glucose, 76.6% (w/w), fructose, 11.2% (w/w); xylose, 7.5% (w/w) and cellobiose, 3.8% (w/w). Fungal cultures grown in tomato pomace syrups showed that the initial biomass of 2.02 g kg−1 increased exponentially after a 4 h lag phase to yield 9.02 g kg−1 at the end of 48 h. The uptake of glucose occurred at 0.64 g/lh. At the end of the fermentation the fungi had consumed 93.4% of the total sugar, displaying a biomass yield of 0.53 g/g. The glucose was totally consumed between 12 and 24 h fermentation and the fungal growth observed up to 48 h was due to xylose and fructose, which started to be used after 12 h.