Screening and optimisation of hydrogen production by newly isolated nitrogen-fixing cyanobacterial strains

Recently, there has been a propensity to postpone dealing with the world's climate concerns until later, resulting in a 1.5 degrees C rise in temperature over the last century. Therefore, interest in biologically derived, inexhaustible energy sources based on solar energy is growing. Cyanobacteria have the potential to produce clean, renewable fuels in the form of hydrogen (H2) gas, derived from solar energy and water. The current study reports the screening 11 cyanobacterial strains isolated from rice paddies and hotsprings for efficient H2 producers. According to our findings, H2 concentrations in the species ranged from 3.6 to 48.9 mmol mg-1 Chl a h-1. H2 production by isolated species was shown to have a 2% positive influence on oxygen (O2) and carbon dioxide (CO2) concentrations and a 2% negative effect on all nitrogen gas (N2) concentrations. It was discovered that at high CO2 concentrations, photosynthesis is enhanced but H2 production is suppressed. Anabaena variabilis BTA-1047 was found to be the most active H2-producing species, with an H2 production activity of 21.3 mmol mg-1 Chl a h-1. Moreover, a 1% O2: 2% CO2 gas mixture doubled the strain activity of H2 production. The findings of the study called into the question the notion that only an anaerobic environment is required for H2 production by N2-fixing cyanobacterial species and explored whether H2 productivity can be increased by stimulating the micro-anaerobic environment with a carbon source. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

There is a growing interest in biologically derived, inexhaustible energy sources based on solar energy, as there has been a tendency to postpone dealing with climate concerns. Cyanobacteria have the potential to produce clean, renewable fuels in the form of hydrogen gas. A recent study screened 11 cyanobacterial strains for efficient hydrogen production and found that the most active species was Anabaena variabilis BTA-1047, with an H2 production activity of 21.3 mmol mg-1 Chl a h-1. The study also questioned the idea that only an anaerobic environment is required for H2 production by cyanobacterial species.