Conversion of biogas to methanol by methanotrophs immobilized on chemically modified chitosan

• Published in: Bioresource technology 2020-11, Vol.315, p.123791-123791, Article 123791
• Main Authors: Patel, Sanjay K.S., Gupta, Rahul K., Kondaveeti, Sanath, Otari, Sachin V., Kumar, Anurag, Kalia, Vipin C., Lee, Jung-Kul
• Format: Article
• Language: English
• Subjects: Chitosan; Greenhouse gas; Immobilization; Methanol; Methanotrophs
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2020.123791

[Display omitted] •Chemically modified chitosan improves immobilization of methanotrophs.•Up to 7.7-fold higher cell loading is obtained on chemically modified chitosan.•Up to 23.9-fold higher methanol production is noted as compared to free cells.•Immobilized cells efficiently produce methanol from raw biogas. In this study, chitosan modified with glutaraldehyde (GLA), 3-aminopropyltriethoxysilane (APTES), polyethyleneimine, and APTES followed by GLA (APTES-GLA) as a support material was used to improve methanol production from biogas. Among these support materials, chitosan-APTES-GLA showed the highest increase in immobilization yield and relative efficiency of Methylomicrobium album up to 56.4% and 97.7%, respectively. Maximum cell loading of 236 mg dry cell mass per g-support was observed for M. album., which is 7.7-fold higher than that of chitosan. The immobilized M. album maintained a 23.9-fold higher methanol production compared to free cells after 8 cycles of reuse; it also produced 6.92 mmol·L−1 methanol from biogas that originated from anaerobic digestion of rice straw, thereby validating its industrial application. This is the first report on the immobilization of methanotrophs on chemically modified chitosans to improve cell loading and relative efficiency, and its potential applications in the conversion of greenhouse gases to methanol.