International Journal of Hydrogen Energy, Vol.44, No.30, 15833-15841, 2019
High NH3-N tolerance of a cheR2-deletion Rhodobacter capsulatus mutant for photo-fermentative hydrogen production using cornstalk
A mutant, JL1601, with a cheR2 gene deletion was constructed with Rhodobacter capsulatus JL1 as the wild type strain. The effects of pH, ammonia nitrogen concentration and light intensity on the photo-fermentative hydrogen production performance of JL1601 were studied. Suitable pH range for hydrogen production with the cheR2(-) mutant migrated from faintly acid to weak alkaline condition, and R.capsulatus JL1601 (cheR2(-)) showed higher NH3-N tolerance. The mutant performed better H-2 production performance than the wildtype under the same illumination condition. The maximum H-2 yield and rate of R.capsulatus JL1601 (cheR2(-)) obtained to be 4406.7 +/- 45.9 mL/L and 54.1 +/- 1.6 mL/(L.h) with the mixture of acetate and butyrate as the carbon sources, which were increased by 36.3% and 12.3% in comparison to those of wildtype, respectively. Practical experiments using acid-enzymatic pretreated cornstalk as the carbon source indicated that, the maximum hydrogen yields by the mutant JL1601 (cheR2(-)) was up to 224.85 +/- 5.18 mL-H-2/g-cornstalk, which increased by 171.43% compared with that of wild type strain. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.