Alternate green approach of spent media utilization for hydrogen and for lipid production

Abstract

In a view to uplift the biodiesel industry as a major energy carrier, new approach of minimizing the waste and utilizing generated waste needs to be explored. The spent media generated from the co-culture system is cost effective and can serve as renewable supplement for mixed-culture based hydrogen (H 2) production and lipid production. Direct conversion of spent media along with crude glycerol (CG) at 20 g/L using heat-shock pretreated wastewater sludge resulted in 38.12 ±0.84 mmol/L of H 2. In another approach, the spent media was used as co-supplement along with fresh media at 3:2 for algal growth, resulting in 0.098 ±0.007 g/L of lipid. The spent media contained dead biomass, residual media nutrients, biomolecules and unutilized glycerol together acting as supplementary source during H 2 and lipid production. According to the closed system results, the H 2 produced (1.47x10 9 L of H 2) can be converted into energy (1.87 x10 4 GJ) for electricity (1.77 x10 4 GJ) and heat (4.32 x10 3 GJ). The produced H 2 can be used as in-house energy source and the lipids can be used as third generation feedstock. The study explores the utilization of CG and spent media valorization towards an efficient closed system approach for a competitive biodiesel industry.

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

“…Reports indicate that photo-fermentation by mixed bacteria using these organic acids as substrates is likely to further enhance substrate conversion efficiency on large scale. In another approach, the spent media from mixed-culture system supplemented with fresh media can be used for hydrogen and lipid production using the closed system as discussed in [153].…”