Bioaugmentation of anaerobic digesters treating lignocellulosic feedstock by enriched microbial consortia

Abstract

Three different bioaugmentation cultures enriched from natural and engineered cellulolytic environments (cow and goat rumen, a biogas reactor digesting sorghum biomass) were compared for their enhancement potential on the anaerobic digestion of wheat straw. Methane yields were determined in batch tests using the Automatic Methane Potential Test System operated for 30 days under mesophilic conditions. All cultures had positive effects on substrate degradation, and higher methane yields were observed in the bioaugmented reactors compared to control reactors set up with standard inoculum. However, the level of enhancement differed according to the type of the enrichment culture. Methane yield in batch reactors augmented with 2% cow rumen derived enrichment culture was increased by only 6%. In contrast, reactors amended with 2% goat rumen derived enrichment culture or with the bioaugmentation culture obtained from the biogas reactor digesting sorghum biomass produced 27 and 20% more methane, respectively. The highest methane yield was recorded in reactors amended with 6% goat rumen derived enrichment culture, which represented an increase by 36%. The microbial communities were quite similar at the end of the batch tests independently of the bioaugmentation sources, indicating that the introduced microbial communities of the enrichment cultures did not dominate the reactors.

Comparative Assessment of Biogas Production Potential of the Most Abundant Agro-residues in Turkey

“…For triticale straw, in addition to the differences in TS and VS values, the differences may be attributed to the trace element addition in the experimental setup in that study [33]. On the other hand, the biomethane potential range is quite wide for wheat straw (150-250 mL/gVSinfluent) [34,35] and our results are in line with the previous studies carried out in Turkey and Germany [23,28]. In another study, the biomethane yield for sunflower head was determined as 211 mL CH4/gVinfluent which was higher than the result obtained from this study [26].…”

“…Physico-chemical properties of the agro-residues & inoculum production potentials of the selected agro-residuals were determined using the Automatic Methane Potential Test System (AMPTS) II (Bioprocess Control, Sweden) with 24 reactors in two AMPTS runs according to the protocol described by Ozbayram et al[23]. The experiments were conducted in 500 mL glass reactors with a working volume of 400 mL.…”

Enhancing methane production from anaerobic co‐digestion of cow manure and barley: Link between process parameters and microbial community dynamics

“…15,16 High cellulolytic activity of the rumen microorganisms (i.e., bacteria, fungi, and protozoa) have been recently reported to contribute to enhanced substrate degradation and elevated methane production in return. [17][18][19] Inoculum to substrate (I:S) ratio is another significant parameter in the assessment of anaerobic batch digesters and the I:S ratio significantly affects the methane production. 20,21 It was shown that methane production rates were clearly different with three experimental ratios and AD of swine slurry should be carried out at the I:S ratio of around 1:1, thereby avoiding reactor imbalances due to volatile fatty acid (VFA) accumulation.…”

Enrichment of Anaerobic Microbial Communities from Midgut and Hindgut of Sun Beetle Larvae (Pachnoda marginata) on Wheat Straw: Effect of Inoculum Preparation

“…The best result of the previous studies was obtained with sheep rumen enrichment culture with a maximum cumulative gas production of 115 mL, which was calculated for the same amount of straw used in this study [46]. Those enrichment cultures were successfully used in bioaugmentation experiments to enhance biogas production [46,47].…”