Phylogenetic identification of lactic acid bacteria isolates and their effects on the fermentation quality of sweet sorghum (Sorghum bicolor) silage

Abstract

Aim To isolate, screen and identify the lactic acid bacteria (LAB) from elephant silage during the process of the fermentation and their effects on the fermentation quality of sweet sorghum silage. Methods and Results The isolated strains were identified based on morphological, physiological and biochemical characteristics as well as 16S rRNA analysis. Seven LAB strains were isolated from elephant grass silage. Three strains (Pediococcus acidilactici (AZZ1), Lactobacillus plantarum subsp. plantarum (AZZ4), L. plantarum subsp. argentoratensis (AZZ7) and one commercial bacteria L. plantarum, ecosyl MTD/1(CB)) were chosen as additives at 6 log colony forming units per gram of fresh sweet sorghum grass in laboratory silos (680 g). Silos for each treatment were opened after 5, 7, 14, 30 and 60 days, respectively. All isolates were characterized as Gram‐positive, catalase‐negative and grow normally in 6·5% NaCl. The strains AZZ1, AZZ2 and AZZ5, were identified as Pediococcus genus while AZZ3, AZZ4, AZZ6 and AZZ7 were Lactobacillus genus. Compared to the control, all the isolates improved the silage quality of sweet sorghum silage, indicated by significantly (P < 0·05) lower pH and ammonia‐nitrogen contents and undesirable micro‐organism counts, and higher lactic acid (LA) contents and ratios of lactic acid/acetic acid. During ensiling, AZZ4 performed better among all of inoculants, indicated by significantly (P < 0·05) decreased on pH and ammonia‐N contents and higher increased on LA contents. Conclusion Strain AZZ4 is recommended as starter culture for sweet sorghum. Significance and Impact of the Study This is the first time to investigate the effects of LAB isolates from elephant grass silage and use them as additives, which is to find out how LAB inoculants improve the fermentation quality of sweet sorghum silage.

Selection of Lactic Acid Bacteria from Alfalfa Silage and Its Effects as Inoculant on Silage Fermentation

“…Isolation of LAB from fresh crop or silage to be used as microbial inoculant can improve silage quality [33] since epiphytic LAB are not always present in sufficient number to ensure efficient fermentation in the silo [34]. The LAB strains identified in the present study by 16S rRNA gene sequencing belonging to W. cibaria, L. plantarum, L. pentosus, L. brevis, L. casei, P. pentosaceus, and P. acidilactici were also found in other studies [8,[35][36][37].…”

“…Thus, it suggests the need to find particular strains adapted to different forages under local conditions. Autochthonous strains of LAB have been already isolated from silages of different forage crops such as elephant grass [8], alfalfa [9], and corn [10]. Strains of L. plantarum and Pediococcus acidilactici isolated from elephant grass silage improved sorghum silage fermentation by decreasing silage pH, butyric acid, and yeast count [8].…”

“…Autochthonous strains of LAB have been already isolated from silages of different forage crops such as elephant grass [8], alfalfa [9], and corn [10]. Strains of L. plantarum and Pediococcus acidilactici isolated from elephant grass silage improved sorghum silage fermentation by decreasing silage pH, butyric acid, and yeast count [8]. However, only few research investigations have been conducted under tropical conditions [11,12].…”

Fermentation quality and aerobic stability of mulberry silage prepared with lactic acid bacteria and propionic acid

“…In the recent years, the demand for animal products has been increasing greatly in many developing countries, but the feedstuff deficiency is the main limit factor for animal husbandry (Sifeeldein et al., ). Therefore, developing new forage resources is a priority to answer the increasing demand for animal products in numerous countries, including China.…”

Silage Fermentation on Sweet Sorghum Whole Plant for Fen-Flavor Baijiu

“…Silage fermentation is a type of solid-state fermentation and is widely applied in feed production. Lactobacillus bacteria are normally used as silage starters for crops to produce amounts of lactic acid through anaerobic respiration, which can inhibit the growth of harmful bacteria and preserve the nutrition of green forage for long periods [ 17 , 18 ]. When Saccharomyces cerevisiae is used as silage starter for sugar crops such as sweet sorghum, the ethanol produced can also inhibit the harmful bacteria [ 19 ].…”