Anaerobic conversion of lactic acid to acetic acid and 1,2-propanediol by Lactobacillus buchneri. Appl Environ Microbiol

ID TNO Animal Nutrition, Lelystad, The Netherlands.
Applied and Environmental Microbiology (Impact Factor: 3.95). 02/2001; 67(1):125-32. DOI: 10.1128/AEM.67.1.125-132.2001
Source: PubMed

ABSTRACT The degradation of lactic acid under anoxic conditions was studied in several strains of Lactobacillus buchneri and in close relatives such as Lactobacillus parabuchneri, Lactobacillus kefir, and Lactobacillus hilgardii. Of these lactobacilli, L. buchneri and L. parabuchneri were able to degrade lactic acid under anoxic conditions, without requiring an external electron acceptor. Each mole of lactic acid was converted into approximately 0.5 mol of acetic acid, 0.5 mol of 1,2-propanediol, and traces of ethanol. Based on stoichiometry studies and the high levels of NAD-linked 1, 2-propanediol-dependent oxidoreductase (530 to 790 nmol min(-1) mg of protein(-1)), a novel pathway for anaerobic lactic acid degradation is proposed. The anaerobic degradation of lactic acid by L. buchneri does not support cell growth and is pH dependent. Acidic conditions are needed to induce the lactic-acid-degrading capacity of the cells and to maintain the lactic-acid-degrading activity. At a pH above 5.8 hardly any lactic acid degradation was observed. The exact function of anaerobic lactic acid degradation by L. buchneri is not certain, but some results indicate that it plays a role in maintaining cell viability.

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    • "Whole-crop maize silage is the major forage fibre source in dairy cow diets in Europe and in the United States, but its aerobic instability could decrease its nutritive value (Wilkinson and Davies, 2013). This problem could be prevented by the use of an inoculant containing Lactobacillus buchneri, a heterofermentative LAB, which could improve the aerobic stability of silages through the production of acetic acid from lactic acid during the anaerobic phase of silage conservation (Oude Elferink et al., 2001). The positive effect of this organism on aerobic stability, when added to maize silage, has been evaluated extensively on maize silage in laboratory experiments (Kleinschmit and Kung, 2006), in farm-scale experiments (Kristensen et al., 2010) and in farm surveys (Mari et al., 2009; Tabacco et al., 2011a). "
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    ABSTRACT: The aim of this research was to study the effects of a commercial inoculant containing Lactobacillus casei and Lactobacillus buchneri that produces ferulate esterase enzymes on fermentation products, aerobic stability, microbial status, dry matter (DM) losses, and digestibility of neutral detergent fibre (aNDF-D) of maize silages ensiled at four stages of maturity. The kernel milk line (ML) was used to time the forage harvest, and 1/6 ML, 2/5 ML, 3/4 ML and black layer (BL) were observed, for harvest stages I, II, III and IV, respectively. Chopped whole plant maize was untreated or treated with L. casei LC32909 and L. buchneri LN40177, which were applied to achieve a final application rate of 1 × 104 cfu/g and 1.0 × 105 cfu/g of fresh forage, respectively. The maize was ensiled in laboratory silos for 260 days before opening. The DM content, starch and ether extract concentrations and mould count increased, whereas water activity, nitrate, ash, water soluble carbohydrates (WSC) and crude protein (CP) contents progressively decreased with increasing maturity at harvest. The 24-h and 48-h aNDF-D were similar for harvest stages I, II and III, whereas they were the lowest in harvest stage IV. The effect of inoculation decreased with increasing DM content at ensiling, and the inoculum was ineffective at the last stage of maturity, probably due to the high epiphytic lactic acid bacteria (LAB) count, low water activity and low sugar content that could have negatively influenced the inoculation outcome. The inoculation lowered the lactic acid, yeast and mould counts and increased acetic acid, 1,2-propanediol, pH, DM losses and aerobic stability in the first three harvest stages, whereas no differences were observed between the treated and untreated silages harvested at the last stage of maturity. Regardless of the treatment, the yeast count fell under the detection limit and the aerobic stability of the silage increased to over 200 hours when the acetic acid content exceeded 25 g/kg DM. Furthermore, the DM losses were closely correlated to the acetic acid production and increased to 80 g/kg of DM in the treated silages harvested at the earliest stage of maturity. The potential milk production, estimated with MILK2006 model ( Shaver et al., 2006,, showed that the greater aNDF-D of the treated silage, which was observed in harvest stages I and III, did not counterbalance the higher DM losses attributable to the L. buchneri activity during ensiling, in terms of milk per Mg of original ensiled DM.
    Animal Feed Science and Technology 11/2014; 198:94–106. DOI:10.1016/j.anifeedsci.2014.10.001 · 2.09 Impact Factor
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    • "There may be some microbes in EM responsible for the production of these acids or some species (e.g. Lactobacillus buchneri) were present that are capable of converting lactic acid to acetic acid in anaerobic conditions (Oude Elferink et al., 2001 "
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    ABSTRACT: This study examined the effects of bacterial inoculants on chemical composition and fermentation indices of barley silage. Barley forage (Youngyang) was harvested at 24% dry matter (DM) and wilted to 47.9% DM. The wilted barley forage was chopped to 3-5 cm length and applied with no inoculant (CON), L. plantarum (1×10(10) cfu/g, LP) or Effective Microorganisms (0.5×10(9) cfu/g, EM). Then the forages were ensiled in four replications for each treatment in 20 L mini silos and stored for 100 days. The contents of crude protein and ether extract were higher in CON silage ensiled for 100-d, while the contents of DM and crude ash were higher in EM silage (p<0.05). The contents of ADF, NDF and hemicellulose as well as the in vitro DM digestibility were not affected by microbial inoculation (p>0.05). The pH, ammonia-N concentration and lactate to acetate ratio were higher (p<0.05) in CON silage, while lactate concentrations were higher (p<0.05) in CON and LP silage. Acetate concentration and lactic acid bacteria was increased (p<0.05) by both inoculants (LP and EM), but propionate concentration and yeast was increased (p<0.05) by EM and LP, respectively. These results indicated that the fermentation quality of barley silage was improved by the application of bacterial inoculants.
    Asian Australasian Journal of Animal Sciences 04/2014; 27(4):511-7. DOI:10.5713/ajas.2013.13617 · 0.56 Impact Factor
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    • "Lactobacillus buchneri appears to be active for longer duration in corn silage and probably this contributes to the present findings. Under anaerobic conditions and low pH, this organism is able to convert lactic acid to acetic acid, ethanol and 1, 2 propanediol (Oude-Elferink et al., 2001). Silages with high ethanol concentration are an indicative of slow decline in pH of ensiled material and having higher final pH values. "
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    ABSTRACT: The effect of ensiling duration on fermentation characteristics, chemical composition, gas production parameters and protein fractions of sweet sorghum silage was studied. Triplicate samples of sweet sorghum were ensiled for 0, 30, 60, 90, and 120 days in laboratory silos. Orthogonal contrasts were used to test linear, quadratic and cubic effects of ensiling time. The results of chemical analysis showed that, ensiling sweet sorghum increased dry matter (DM), soluble crude protein (SCP), ash and acid detergent lignin (ADL) concentrations compared to fresh sweet sorghum (P<0.01), however, net energy for lactation (NEl) and organic matter digestibility (OMD) decreased (P<0.01) compared to fresh material. The concentrations of ammonia nitrogen, lactic acid, acetic acid, ethanol and the amount of effluent increased significantly (P<0.01) with advancing ensiling period. The concentration of lactic acid was higher than other fermentation acids. DM and neutral detergent fibre (aNDF) concentrations decreased (P<0.01), while non-fibre carbohydrates increased linearly (P<0.01) with advancing ensiling process. The greatest amount of water soluble carbohydrate (WSC) loss occurred within the first 30 day of ensiling (from 166 to 96.7 g/kg DM) and this trend continued quadratically (P<0.01) with advancing ensiling time. Silages had lower (P<0.001) CP concentration compared with fresh forages (54.90 versus 61.80 g/kg DM) while time of ensiling did not affect (P<0.05) the CP concentration. Net energy for lactation (NEl) and organic matter digestibility (OMD) estimated from gas production technique were lower (P<0.01) for silages compared to fresh material and they decreased linearly (P<0.05) by advancing ensiling time. The results showed that, increasing ensiling time from 30 to 120 days decreased DM, WSC, aNDF and OMD concentrations and NEL content of sweet sorghum. To cite this article: Zafari Naeini S, N Khodambashi Emami, E Rowghani, A Bayat, 2014. Influence of ensiling time on chemical composition, fermentation characteristics, gas production and protein fractions of sweet sorghum silage.
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