The preservation of lactobacilli: A comparison of three methods

Barbour, Elizabeth Anne; Priest, Fergus G.

doi:10.1111/j.1472-765x.1986.tb01518.x

Cited by 18 publications

(9 citation statements)

References 8 publications

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“…bulgaricus and, if possible, to determine a target site responsible for cell death. The benefits of using glycerol, SMP and sugars (trehalose) in the protection of bacterial cells during freezing are in agreement with previously published reports (Moss and Speck 1963 ;Barbour and Priest 1986 ;Berny and Hennebert 1991). The exact mechanisms by which these compounds and other cryoprotectors provide protection against freeze injury in bacteria are not all clearly understood.…”

Section: Discussionsupporting

confidence: 87%

Evidence of membrane damage in Lactobacillus bulgaricus following freeze drying

Castro¹,

Teixeira²,

Kirby³

1997

J Appl Microbiol

134

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H.P. CASTRO, P.M. TEIXEIRA AND R. KIRBY. 1997. T h e mechanism of inactivation of Lactobacillus bulgaricus due to freeze drying was investigated. Cells were freeze-dried i n skim milk powder, maltodextrin, glycerol, trehalose and water. Results are presented confirming previous authors' observations regarding membrane damage during freeze drying.I n an attempt to define more clearly the nature of this damage, further experiments were carried out. Results show that following freeze drying changes occur in the unsaturated : saturated fatty acid ratio, a decrease in the activity of the membrane-bound enzyme ATPase and a loss of ApH.

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Section: Discussionsupporting

confidence: 87%

Evidence of membrane damage in Lactobacillus bulgaricus following freeze drying

Castro¹,

Teixeira²,

Kirby³

1997

J Appl Microbiol

134

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“…If decarboxylation by the yeast is rate limiting in this process, mixed cultures will provide rapid transformation into the ethyl forms. Alternatively, one of the major differences between a pureyeast fermentation and a mixed fermentation with lactic acid bacteria is a greater reduction in pH due to lactic acid production by the bacteria (2,14). It is possible that the reduction of 4-VP occurs more favorably under these conditions.…”

Section: Discussionmentioning

confidence: 99%

Decarboxylation of Substituted Cinnamic Acids by Lactic Acid Bacteria Isolated during Malt Whisky Fermentation

Beek

Priest

2000

Appl Environ Microbiol

131

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Seven strains of Lactobacillus isolated from malt whisky fermentations and representing Lactobacillus brevis, L. crispatus, L. fermentum, L. hilgardii, L. paracasei, L. pentosus, and L. plantarum contained genes for hydroxycinnamic acid (p-coumaric acid) decarboxylase. With the exception of L. hilgardii, these bacteria decarboxylated p-coumaric acid and/or ferulic acid, with the production of 4-vinylphenol and/or 4-vinylguaiacol, respectively, although the relative activities on the two substrates varied between strains. The addition of p-coumaric acid or ferulic acid to cultures of L. pentosus in MRS broth induced hydroxycinnamic acid decarboxylase mRNA within 5 min, and the gene was also induced by the indigenous components of malt wort. In a simulated distillery fermentation, a mixed culture of L. crispatus and L. pentosus in the presence of Saccharomyces cerevisiae decarboxylated added p-coumaric acid more rapidly than the yeast alone but had little activity on added ferulic acid. Moreover, we were able to demonstrate the induction of hydroxycinnamic acid decarboxylase mRNA under these conditions. However, in fermentations with no additional hydroxycinnamic acid, the bacteria lowered the final concentration of 4-vinylphenol in the fermented wort compared to the level seen in a pure-yeast fermentation. It seems likely that the combined activities of bacteria and yeast decarboxylate p-coumaric acid and then reduce 4-vinylphenol to 4-ethylphenol more effectively than either microorganism alone in pure cultures. Although we have shown that lactobacilli participate in the metabolism of phenolic compounds during malt whisky fermentations, the net result is a reduction in the concentrations of 4-vinylphenol and 4-vinylguaiacol prior to distillation.

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“…Conversely, heat treatments, which stimulate active trehalose biosynthesis, concurrently increase the freeze tolerance of germinating conidiospores of Neurospora crassa [79]. Indeed, for many years, the compatible solutes sucrose and glycerol have routinely been used as additives for microbial samples to be stored frozen or to be freeze dried [80,81] and exogenously added trehalose at a concentration of 0.3 M has been shown to increase the viability and preserve the acidification properties of cultures of Lactobacillus bulgaricus used in the dairy industry, to repeated freeze‐thaw cycles [82]. Similarly in vitro, a wide range of compatible solutes, including glycerol, glycine betaine, trehalose, sucrose, proline and DMSP, have been demonstrated to inhibit the denaturation of isolated cold sensitive enzymes such as phosphofructokinase during freeze‐thaw cycles [83–86].…”

Section: Ecological Benefits To Individual Cellsmentioning

confidence: 99%

Ecological significance of compatible solute accumulation by micro-organisms: from single cells to global climate

2000

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The osmoadaptation of most micro-organisms involves the accumulation of K(+) ions and one or more of a restricted range of low molecular mass organic solutes, collectively termed 'compatible solutes'. These solutes are accumulated to high intracellular concentrations, in order to balance the osmotic pressure of the growth medium and maintain cell turgor pressure, which provides the driving force for cell extension growth. In this review, I discuss the alternative roles which compatible solutes may also play as intracellular reserves of carbon, energy and nitrogen, and as more general stress metabolites involved in protection of cells against other environmental stresses including heat, desiccation and freezing. Thus, the evolutionary selection for the accumulation of a specific compatible solute may not depend solely upon its function during osmoadaptation, but also upon the secondary benefits its accumulation provides, such as increased tolerance of other environmental stresses prevalent in the organism's niche or even anti-herbivory or dispersal functions in the case of dimethylsulfoniopropionate (DMSP). In the second part of the review, I discuss the ecological consequences of the release of compatible solutes to the environment, where they can provide sources of compatible solutes, carbon, nitrogen and energy for other members of the micro-flora. Finally, at the global scale the metabolism of specific compatible solutes (betaines and DMSP) in brackish water, marine and hypersaline environments may influence global climate, due to the production of the trace gases, methane and dimethylsulfide (DMS) and in the case of DMS, also couple the marine and terrestrial sulfur cycles.

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The preservation of lactobacilli: A comparison of three methods

Cited by 18 publications

References 8 publications

Evidence of membrane damage in Lactobacillus bulgaricus following freeze drying

Evidence of membrane damage in Lactobacillus bulgaricus following freeze drying

Decarboxylation of Substituted Cinnamic Acids by Lactic Acid Bacteria Isolated during Malt Whisky Fermentation

Ecological significance of compatible solute accumulation by micro-organisms: from single cells to global climate

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