Enzymatic Pretreatment of Byproducts from Soapstock Splitting and Glycerol Processing for Improvement of Biogas Production

Abstract

This study investigated acid splitting wastewater (ASW) and interphase (IF) from soapstock splitting, as well as matter organic non glycerol (MONG) from glycerol processing, as potential substrates for biogas production. Batch and semicontinuous thermophilic anaerobic digestion experiments were conducted, and the substrates were preliminary treated using commercial enzymes kindly delivered by Novozymes A/C. The greatest enhancement in the batch digestion efficiency was achieved when three preparations; EversaTransform, NovoShape, and Lecitase were applied in the hydrolysis stage, which resulted in the maximum methane yields of 937 NL/kg VS and 915 NL/kg VS obtained from IF and MONG, respectively. The co-digestion of 68% ASW, 16% IF, and 16% MONG (wet weight basis) performed at an organic loading rate (OLR) of 1.5 kg VS/m3/day provided an average methane yield of 515 NLCH4/kg VSadded and a volatile solid reduction of nearly 95%. A relatively high concentration of sulfates in the feed did not significantly affect the digestion performance but resulted in an increased hydrogen sulfide concentration in the biogas with the peak of 4000 ppm.

A Thermosiphon Photobioreactor for Photofermentative Hydrogen Production by Rhodopseudomonas palustris

“…Crude glycerol, a by-product of the biodiesel industry, has gained increasing attention as a substrate in biological waste to value-added product processes—some of these processes include biogas production by anaerobic digestion [ 35 , 36 , 37 ], lipid production [ 38 ], and photofermentative hydrogen production [ 7 ], with Pott et al [ 7 ] reporting a conversion efficiency (crude glycerol to hydrogen gas) that is close to 90% of the theoretical maximum when using R. palustris . The combination of industrial waste streams as a carbon substrate and a cost-efficient PBR would not only decrease the cost of photofermentative hydrogen production [ 34 ], but also aid in moving towards sustainable hydrogen production and green energy.…”

Biodegradation of Synthetic Organic Compounds by Methanogenic Microbiome as an Alternative Approach for Wastewater Purification and Energy Production

“…The pretreatment of soapstock with expensive additives, such as enzymes, to increase the efficiency of degradation is now widespread [50,51]. Commercial enzymes [50] or special strains of microorganisms are used for this purpose. For example, Staphylococcus haemolyticus was used to perform enzymatic hydrolysis of lipids [51].…”