Efficiency enhancement of H2 production by a newly isolated maltose-preferring fermentative bio-hydrogen producer of Clostridium butyricum NH-02

Bio-H-2 production with fermentative bacteria provides environmental-friendly pathways for renewable bioenergy recovery and wastes reutilization from organic biomass wastes and wastewater. In the present study, a maltose-preferring fermentative bio-H-2 producing strain was isolated from humus-rich soil and identified as Clostridium butyricum NH-02 (MT229351). The optimal fermentation substrate, culture temperature and initial pH for strain NH-02 were studied for H-2 yield enhancement and further investigations. The maximum cumulative H-2 production of 1.80 L-H-2/L-medium, H-2 yield of 1.90 mol-H-2/mol-RS (reducing sugar), RS consumption of 93.09% and cell dry weight of 1.88 g/L were obtained after a 24 h fermentation under the optimal condition of 10 g/L maltose, initial pH 7.0 and 35 degrees C. To our knowledge, strain NH-02 was the first reported bio-H-2 producer within C. butyricum having a higher H-2 yield from maltose than that from glucose. The experimental results indicated that C. butyricum NH-02 is an efficient and promising candidate for bio-hydrogen recovery from maltose-rich wastewater.