Improving production of biohydrogen from COOH-functionalized multiwalled carbon nanotubes through Co-immobilization with Clostridium pasteurianum

Biohydrogen is a promising clean energy. Multiple researchers have successfully increased hydrogen production by augmenting nanomaterials with anaerobic hydrogen-producing microorganisms. Herein, a novel approach is developed in which a pure strain of Clostridium pasteurianum CH5 is co-immobilized with carboxylic-acid-functionalized multiwalled carbon nanotubes (MWCNT-COOH). The direct co-immobilization of C. pasteurianum CH5 with 800-mg/L MWCNT-COOH improves the hydrogen yield (HY) to 2.43 mol H2/mol glucose. When C. pasteurianum CH5 and 800 mg/L MWCNT-COOH are preincubated for 24 h, the HY increases to 2.38 mol H2/mol glucose, a 46.9% increase relative to the control (without co-immobilization) and a 133.3% increase relative to the conventional suspended growth of C. pasteurianum CH5 mixed with the same concentration of MWCNT-COOH. These results indicate that bringing nanomaterials into closer contact with microorganisms can serve as a feasible and simple approach for biohydrogen production. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.