Efficient succinic acid production using a biochar-treated textile waste hydrolysate in an in situ fibrous bed bioreactor

Textile waste contains biodegradable fraction which can be used as an alternative feedstock for succinic acid production. The feasibility of bioconversion of biochar-treated textile waste hydrolysate into succinic acid was evaluated. A substrate loading of 9% was applied to hydrolyze mixed textile waste and the resultant glucose-rich hydrolysate with dyestuff was collected after enzymatic hydrolysis. Biochar from different pyrolysis temperatures (400–700 °C)and different dosages of the selected biochar (1–5%)were applied to remove colorants. The results showed that biochar had a good performance at a dosage of 2 w/w % on removal of colorant inhibitors. There was no negative effect observed during the subsequent fermentation. After optimization of fermentation media in shake flasks, the resultant succinic acid titer reached 19.6 g/L with a SA yield of 0.76 g/g, supplemented with 30 g/L tryptone. The in situ fibrous bed bioreactor (isFBB)can further improve SA titer, up to 28.8 g/L corresponding to a yield of 0.61 g/g without pH control. Furthermore, a shorter lag phase during succinic acid fermentation in isFBB was observed. It can be concluded that a novel textile waste-based biorefinery approach for succinic acid production aided by biochar sorption was successfully developed.