Evaluation of biodegradable plastics as solid hydrogen donors for the reductive dechlorination of fthalide by Dehalobacter species

Biodegradable plastics (BPs) were evaluated for their applicability as sustainable and solid H2 donors for microbial reductive dechlorination of 4,5,6,7-tetrachlorophthalide (fthalide). After a screening test of several BPs, the starch-based plastic (SP) that produced the highest levels of H2 was selected for its use as the sole H2 donor in this reaction. Fthalide dechlorination was successfully accomplished by combining an H2-producing SP culture and a KFL culture containing Dehalobacter species, supplemented with 0.13% and 0.5% SP, respectively. The efficiency of H2 use in dechlorination was evaluated in a combined culture containing the KFL culture and strain Clostridium sp. Ma13, a new isolate that produces H2 from SP. Results obtained with this culture indicated increased H2-fraction for fthalide dechlorination much more in this culture than in compared with a KFL culture supplemented with 20 mM lactate, which are 0.75 H2·glucose−1 and 0.015 H2·lactate−1 in mol ratio, respectively.