Biological hydrogen production from nitrogen-deficient substrates.

Area of Science:

• Biotechnology
• Renewable Energy
• Microbiology

Background:

• Dark fermentation by mixed bacterial cultures is a method for renewable hydrogen (H2) production.
• Nitrogen (N)-deficient feedstocks present challenges for conventional fermentative H2 production.

Purpose of the Study:

• To investigate the feasibility of producing H2 from N-deficient feedstocks using an N2-fixing mixed bacterial culture.
• To evaluate the H2 yields from glucose and sugarcane using this approach.

Main Methods:

• Utilized a mixed bacterial culture capable of fixing atmospheric nitrogen (N2).
• Fermented N-deficient media and sugarcane feedstock under dark conditions.
• Quantified hydrogen (H2) production in milliliters per gram of substrate and moles per mole of glucose/volatile solids.

Main Results:

• Achieved up to 240 mL H2/g glucose (1.9 mol H2/mol glucose) from a medium initially lacking combined N.
• Obtained promising yields from sugarcane: 170 mL H2/g volatile solids (7.5 mmol H2/g volatile solids).

Conclusions:

• Dark fermentation with N2-fixing mixed cultures is a viable strategy for H2 production from N-deficient feedstocks.
• This method offers potential economic and environmental benefits, including reduced costs and improved effluent quality for subsequent bioconversion.