Sharpea and Kandleria are lactic acid producing rumen bacteria that do not change their fermentation products when co-cultured with a methanogen

Abstract

Sharpea and Kandleria are associated with rumen samples from low-methane-emitting sheep. Four strains of each genus were studied in culture, and the genomes of nine strains were analysed, to understand the physiology of these bacteria. All eight cultures grew equally well with d-glucose, d-fructose, d-galactose, cellobiose, and sucrose supplementation. d-Lactate was the major end product, with small amounts of the mixed acid fermentation products formate, acetate and ethanol. Genes encoding the enzymes necessary for this fermentation pattern were found in the genomes of four strains of Sharpea and five of Kandleria. Strains of Sharpea produced traces of hydrogen gas in pure culture, but strains of Kandleria did not. This was consistent with finding that Sharpea, but not Kandleria, genomes contained genes coding for hydrogenases. It was speculated that, in co-culture with a methanogen, Sharpea and Kandleria might change their fermentation pattern from a predominately homolactic to a predominately mixed acid fermentation, which would result in a decrease in lactate production and an increase in formation of acetate and perhaps ethanol. However, Sharpea and Kandleria did not change their fermentation products when co-cultured with Methanobrevibacter olleyae, a methanogen that can use both hydrogen and formate, and lactate remained the major end product. The results of this study therefore support a hypothesis that explains the link between lower methane yields and larger populations of Sharpea and Kandleria in the rumens of sheep.

Metabolic Hydrogen Flows in Rumen Fermentation: Principles and Possibilities of Interventions

“…In comparison, fewer studies (Chen and Wolin, 1977;Latham and Wolin, 1977) have examined the competition for H 2 between methanogens and other hydrogenotrophs, such as succinate and propionate producers, at the basal H 2 concentrations resulting from fermentation-evolving H 2 . A recent experiment studied the competition for [H] between a methanogen and lactate producers Sharpea and Kandleria (Kumar et al, 2018). Pure cultures of rumen hydrogenotrophs, such as those isolated in the Hungate 1000 Project (Kelly, 2016), could be screened for kinetic parameters of H 2 incorporation and H 2 thresholds.…”

“…Low CH 4 -producing sheep also had higher rumen concentration of lactate, and the lactate dehydrogenases that differed the most between the low-and the high-producing CH 4 sheep associated phylogenetically with S. azabuensis and K. vitulina (Kamke et al, 2016). Several strains of Sharpea and Kandleria that produced predominantly lactate and small amounts of formate, ethanol and acetate, did not change their fermentation products when growing with a methanogen (Kumar et al, 2018).…”

Influence of the artificial sodium saccharin sweetener Sucram®on the microbial community composition in the rumen content and attached to the rumen epithelium in dairy cattle: A pilot study

“…Several OTUs which were identified as potentially hemicellulolytic and proteolytic ( Prevotella, OTUs 5, 11, 14, 33, and 38) were found to be in higher abundance in samples supplemented with Sucram ® in comparison to baseline samples. Additionally, some OTUs were related to bacteria known to produce SCFAs such as lactate, acetate, succinate and propionate ( Sharpea and Prevotella , OTUs 3, 11, 14, 33, 38 and 43) [65–67]. This suggests that cattle exposed to Sucram ® may be more efficiently degrading non-cellulose substrates, thereby potentially increasing concentrations of certain SCFAs.…”

Effects of Starter Feeds of Different Physical Forms on Rumen Fermentation and Microbial Composition for Pre-weaning and Post-weaning Lambs

“…The main fermented products of sharpea in rumen of sheep were lactates, and formation of lactates promoted further fermentation of sharpea, urged lactates to change into butyrate, which led to produce lower H 2 compared to traditional fermentation directly from carbohydrate to butyrate and reduced production of CH 4 in rumen (36,37).…”