Insight into the key limiting factors affecting anaerobic fermentation quality and bacterial community of sweet sorghum by irradiation sterilization and microbiota transplant

Abstract

Biomass microbiota and chemical constituent are closely associated with final anaerobic fermentation performance. But the limiting factors affecting anaerobic fermentation quality and bacterial community have been rarely explored. This study aimed to elucidate the relative contribution of initial microbiota and chemical constituent of sweet sorghum on its final anaerobic fermentation quality. Sweet sorghum at two developmental stages (heading-stage, G1; hard-dough-stage, G2) was treated as follows: G1 microbiota + sterilized G1 (M1C1), G2 microbiota + sterilized G1 (M2C1), G1 microbiota + sterilized G2 (M1C2), and G2 microbiota + sterilized G2 (M2C2). The results showed that chemical constituent rather than microbiota changes remarkably influenced the production of lactic acid, propionic acid and ammonia-N, the relative abundance of Lactobacillus, Weissella, Lactococcus, Pediococcus, and Pantoea of sweet sorghum after anaerobic fermentation. The chemical constituent was the key limiting factor affecting the anaerobic fermentation quality of sweet sorghum. This study could provide a reference for clarifying the key limiting factors affecting anaerobic fermentation and making recommendations for production. Graphical Abstract

Synergistic enhancement of chemical composition, fermentation characteristics, and microbial community dynamics in triticale silage by inoculation with Streptococcus bovis and Lactobacillus plantarum

“…Microbial communities play a crucial role in the silage fermentation quality [25]. In this study, we observed a clear succession of Proteobacteria to Firmicutes before and after fermentation, which is consistent with the literature [25,29,30]. This can be mainly attributed to the acidic environment, which suppresses the growth of acid-sensitive bacteria (Enterococcus, Staphylococcus, Yeast, Mold, etc.)…”

“…In line with this, several studies have demonstrated that compared with LAB-based silage, the use of S. bovis results in a reduction of 30% or more in the doubling time [27,28], leading to faster pH reduction in silage, similar to Enterococcus faecium [10]. Previous studies have shown that LAB additives reduce DM and CP loss [29,30]. In the present study, LAB treatment resulted in less DM loss than in the CON group.…”

“…On days 3 and 7, the LA and AA concentrations were higher in the ST and LS groups, but their LA/AA ratios were signi cantly lower than those in the CON and LP groups. In contrast, Zhao et al [30] reported that Leuconostoc lactis and Weissella confusa had relatively high LA/AA ratios during ensiling. The reason for this discrepancy could be that S. bovis functions as a quick starter during fermentation, encouraging the growth of homofermentative LAB(producing LA) at the beginning of fermentation, while accelerating the growth of heterofermentative LAB (producing AA).…”

“…The pH of triticale before ensiling was 6. 30 3). The interaction between the treatments and ensiling days signi cantly (P < 0.05) affected pH, LA, and AA concentrations.…”