The Stool Microbiome in African Ruminants: A Comparative Metataxonomic Study Suggests Potential for Biogas Production

Abstract

Lignocellulosic biomass is a promising substrate for anaerobic digestion (AD) in renewable energy generation but presents a significant challenge during the hydrolysis stage of conventional AD due to the recalcitrant nature of this biomass substrate. Rumen fluid is often employed as a bioaugmentation seed to enhance hydrolysis in the AD of lignocellulosic substrates due to its richness in hydrolytic bacteria. However, using rumen fluid to enhance AD processes presents substantial hurdles, including the procurement difficulties associated with rumen fluid and ethical concerns. In this study, the fecal microbiota of 10 African ruminant species from a large zoological park (Bioparc) in Valencia, Spain, were studied using 16S rRNA gene amplicon sequencing. In this study, the fecal microbiota of 10 African ruminant species from a large zoological park (Bioparc) in Valencia, Spain, were studied using 16S rRNA gene amplicon sequencing. The investigation revealed potential similarities between the fecal microbiota from the African ruminants’ and cows’ rumen fluids, as suggested by theoretical considerations. Although direct comparative analysis with cow rumen fluid was not performed in this study, the theoretical framework and existing literature hint at potential similarities. According to our results, the Impala, Blesbok, Dikdik and Bongo ruminant species stood out as having the greatest potential to be used in bioaugmentation strategies. Key genera such as Fibrobacter, Methanobrevibacter, and Methanosphaera in Impala samples suggested Impala rumen fluid’s involvement in cellulose breakdown and methane production. Blesbok and Dikdik exhibited a high abundance of Bacillus and Atopostipes, potentially contributing to lignin degradation. The richness of Prevotellaceae and Rikenellaceae in the Bongo fecal samples is probably associated with structural carbohydrate degradation. Taken together, our results shed light on the microbial ecology of the gut contents of a whole set of Bovidae ruminants and contribute to the potential application of gut microbiota in AD.