Trends in designing microbial silage quality by biotechnological methods using lactic acid bacteria inoculants: a minireview

Abstract

Ensiling is one of the best known method to preserve fodder. The forage before ensiling intended for silages usually contains a low number of lactic acid bacteria (LAB), so it is necessary to apply starter cultures of selected strains. Traditionally, LAB starter cultures were applied to lower the pH by producing lactic acid and to inhibit the growth of undesirable epiphytic microorganisms by competing for nutrients. Nowadays, LAB inoculants have become an effective tool for creating microbial quality of silages by selecting species with extraordinary features. Epiphytic microflora characteristic of plant material used for the production of silages and the sources of undesirable microflora in the ensiling process are discussed. This review focuses on the most frequently studied issues related to the microbial silage quality and the recent trends in increasing the quality by LAB inoculants, with respect to recent directions for selecting types of modern LAB for inoculation. Among them, the main trends described were prevention of the growth of filamentous fungi and detoxification of mycotoxins by LAB inoculants, inhibition of yeast growth by LAB present in preparations and limiting the development of pathogenic bacterial microflora through controlled fermentation with the participation of LAB and the presence of their metabolites.

Effects of natamycin and <i>Lactobacillus buchneri</i> on the fermentative process and aerobic stability of maize silage

“…According to Muck et al (2018), the facultative heterofermentative LAB which ferment hexoses, i.e., glucose, are the same as obligate homofermenters which produce almost exclusively lactic acid. In contrast, the obligate heterofermenters produce other compounds from hexoses in addition to lactic acid, including acetic acid (Muck et al, 2018;Fabiszewska et al, 2019). After opening the silo, the present yeast metabolizes lactate and degrades silage, which raises the mass pH reducing its nutritional value (Ranjit et al, 2002) and…”

“…Moreover, the quality also depends on additives such as inoculants (e.g. lactic acid bacteria -LAB), chemicals and enzymes (Muck et al, 2018;Fabiszewska et al, 2019) that improve the fermentation process and dry matter (DM) recovery of the silages (Kung et al, 2018). The high content of lactic acid produced during anaerobic fermentation together with the residue of soluble carbohydrates makes maize silage vulnerable when exposed to air (McDonald et al, 1991).…”

Discovery and characterisation of novel circular bacteriocin plantacyclin B21AG fromLactobacillus plantarumB21

“…Lactic acid bacteria (LAB) have been long associated with food and feed fermentation, specifically as a starter culture in the production of fermented meat, vegetables, fruits, alcoholic beverages, dairy products and silage [6, 7]. They have been shown to inhibit the growth of food spoilage bacteria, as well as have a beneficial influence on nutrition, organoleptic and shelf-life characteristics of fermented products [8–10].…”

Criteria for lactic acid bacteria screening to enhance silage quality

“…These bacteria are essential for spontaneous fermentation; however, they are often present in low populations (<5 log of colonyforming units (CFU) per g substrate) or even below detection levels (<2 log CFU) per g substrate) (Cai et al 1999;Carvalho et al 2017;Fabiszewska et al 2019;Amaral et al 2020). The lactic acid produced by LAB is primarily responsible for silage conservation, so this is the main group of bacteria that has been studied as an inoculant (Muck et al 2018;Fabiszewska et al 2019;Wilkinson and Muck 2019). Some species or strains of LAB can produce acetic acid, ethanol, CO 2 , 1,2-propanediol and other compounds through different metabolic pathways of carbohydrate use (Von Wright and Axelsson 2012).…”