Effect of rumen fungi on potential of biogas production in anaerobic digesters fed with different lignocellulosic compounds

Abstract

Although lignocellulosic biomass are considered as an alternative biogas source, they also cause rate limitation in hydrolysis step of anaerobic digestion process, negative effect on the performance of anaerobic digesters and reduction in yield. Thus, they can be also defined as a significant problem in energy production from animal manure, microalgae and macroalgae. Anaerobic rumen fungi can be seen as a potential treatment method to improve the biogas production because they produce pretty much hydrolyze enzymes. In this study, effects of anaerobic rumen fungi on the performance of anaerobic digesters and biogas production from different lignocelluloosic compounds and also microbial community dynamics during anaerobic digestion process were investigated. In the different three sets, it was examined that effects of bioaugmentation with anaerobic rumen fungi at various ratios of inoculums on biogas production of anaerobic digesters fed with animal manure, microalgae and macroalgae respectively. The highest biogas productions reached 5500 ml in digester R2, 6250 ml in digester F5 and 3500 ml in digester A1. It was also found that the highest methane productions are 60% for animal manure, 57% for microalgae H. pluvialis and 54,7% for macroalgae Ulva lactuca due to addition of anaerobic rumen fungi. Changes in quantity and diversity of bacterial and archaeal communities were detected by lllumina MiSeq sequencing technology. Changes in the number of total cells of fungi were analysed by qPCR to show effect of anaerobic rumen fungi on biogas production from different lignocellulosic compounds.