Production and optimization of biohydrogen from saccharolytic actinobacterium, Streptomyces rubiginosus (SM16), using sugarcane molasses

ABSTRACT

The Actinobacteria are known to produce secondary metabolites like antibiotics, enzymes and pigments and also used in bioremediation. Recently the Actinobacteria have also been reported as a source of biofuels too. Here, the hydrogen production was carried out at different concentrations of sugarcane molasses, pH and temperature through dark H₂ fermentation using the actinobacterium Streptomyces rubiginosus (SM16) isolated from a sugarcane molasses dumping site. The maximum biohydrogen production rate was found to be 296 ± 0.042 mL/L at 4% sugarcane molasses. At the optimized pH of 7.0, the maximum biohydrogen production rate was 283 ± 0.015mL/L, whereas at the optimized temperature of 30°C, the yield of biohydrogen was 266 ± 0.022 mL/L using the effective inoculum SM16. The maximum hydrogen production (407.33 ± 5.03 mL/L) was recorded in the optimized fermentation medium with sugarcane molasses 4%, pH 7.0 and temperature 30°C. Gas chromatography (GC) and high performance liquid chromatography (HPLC) analysis proved the presence of organic acid (tartaric acid – 35.7%) and other volatile fatty acids along with H₂ gas. Hence, the actinobacterium Streptomyces rubiginosus (SM16) is considered a promising source for biohydrogen production.

KEYWORDS:

• Actinobacteria
• bioenergy
• dark fermentation
• biohydrogen
• gas chromatography

Acknowledgements

The authors are grateful to the Vice Chancellor and the Registrar, Periyar University, for providing essential facilities to carry out this work. AS thanks the Department of Biotechnology (DBT Ref. No: BT/ PR 5426/ AAQ/ 3/ 599/ 2012, Date: 10.3.2015) for providing funds in the form a fellowship.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Department of Biotechnology, Ministry of Science and Technology [grant number DBT Ref. No: BT/ PR 5426/ AAQ/ 3/ 599/ 2012, Date: 10.3.2015].