Hydrogen production by a novel Klebsiella pneumoniae strain from sheep rumen uses corn straw as substrate

Abstract

Lignocellulosic biomass (LB)-based hydrogen-biofuel represents a promising, sustainable, clean, and renewable energy resource for meeting the world's ever-increasing energy demand while reducing environmental problems caused by combustion of fossil energy and accumulation of crop straw. However, due to the lack of strains that can directly produce hydrogen from cheap cellulose feedstocks, the high cost of hydrogen production from biomass fermentation has become a key problem limiting its large-scale production. Therefore, finding fermentation strains that can ferment cellulose feedstocks directly has become the key to overcoming the bottleneck that limits the biomass-based hydrogen production. In this study, we reported for the first time that the Klebsiella pneumoniae Y7-3 cellulose-degrading strain isolated from the rumen of sheep in Inner Mongolia was able to directly produce high-yield hydrogen with cheap straw as raw materials. Anaerobic fermentation with 50 g L−1 of corn straw as the carbon source could produce 1253.72 ± 55.67 mL/L of hydrogen in 24 h. To further improve the hydrogen production from corn straw, some regulatory factors were used. 30 mg/L FeSO4, NiCl2 (70 mg/L) or formic acid (5 g L−1) increased the hydrogen production by 25.72%, 17.89% or 331.07%, respectively. This work provides a new insight for microbial hydrogen production.