Seed Pretreatment for Increased Hydrogen Production Using Mixed-Culture Systems with Advantages over Pure-Culture Systems

Vinayak Laxman Pachapur,Satinder Kaur Brar,Preetika Pachapur,Gerardo Buelna,Prianka Kutty,Yann Le Bihan,Rosa Galvez-Cloutier

doi:10.3390/en12030530

Abstract

Hydrogen is an important source of energy and is considered as the future energy carrier post-petroleum era. Nowadays hydrogen production through various methods is being explored and developed to minimize the production costs. Biological hydrogen production has remained an attractive option, highly economical despite low yields. The mixed-culture systems use undefined microbial consortia unlike pure-cultures that use defined microbial species for hydrogen production. This review summarizes mixed-culture system pretreatments such as heat, chemical (acid, alkali), microwave, ultrasound, aeration, and electric current, amongst others, and their combinations to improve the hydrogen yields. The literature representation of pretreatments in mixed-culture systems is as follows: 45–50% heat-treatment, 15–20% chemical, 5–10% microwave, 10–15% combined and 10–15% other treatment. In comparison to pure-culture mixed-culture offers several advantages, such as technical feasibility, minimum inoculum steps, minimum media supplements, ease of operation, and the fact it works on a wide spectrum of low-cost easily available organic wastes for valorization in hydrogen production. In comparison to pure-culture, mixed-culture can eliminate media sterilization (4 h), incubation step (18–36 h), media supplements cost ($4–6 for bioconversion of 1 kg crude glycerol (CG)) and around 10–15 Millijoule (MJ) of energy can be decreased for the single run.

Highlights

Hydrogen can be used as a clean source of energy [1] that on combustion produces water vapor with non-greenhouse gas as the by-product [2]
Hydrogen production is carried out using chemical/physical methods such as electrolysis, production is carried out using chemical/physical methods suchisas electrolysis, steam steamHydrogen reforming, and thermal processing that require energy-intensive steps, very expensive and reforming, and thermal processing that require energy-intensive steps, is very expensive and are exhaustive as they are dependent on fossil fuels [6]
This study indicated that a combination of heat and acid-treatment provided a stronger reaction to degrade organic matter and resulted in a higher hydrogen yield [110]

Summary

Introduction

Hydrogen can be used as a clean source of energy [1] that on combustion produces water vapor with non-greenhouse gas as the by-product [2]. Hydrogen combustion produces large amounts of energy (143 MJ/kg), being 50% more efficient in comparison to using gasoline (43–57 MJ/kg) [3]. Hydrogen production is carried out using chemical/physical methods such as electrolysis, production is carried out using chemical/physical methods suchisas electrolysis, steam steamHydrogen reforming, and thermal processing that require energy-intensive steps, very expensive and reforming, and thermal processing that require energy-intensive steps, is very expensive and are exhaustive as they are dependent on fossil fuels [6]. In theatbiological method ofand hydrogen hydrogen less on energy be contrast, carried out ambient conditions is less production [7]

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