Cell membrane fatty acid changes and desaturase expression of Saccharomyces bayanus exposed to high pressure homogenization in relation to the supplementation of exogenous unsaturated fatty acids.

Diana I Serrazanetti,Alessandra Russo,Lorenzo Siroli,Francesca Patrignani,Fausto Gardini,Rosalba Lanciotti,Lucia Vannini

doi:10.3389/fmicb.2015.01105

Diana I Serrazanetti, Alessandra Russo + Show 5 more

Open Access

https://doi.org/10.3389/fmicb.2015.01105

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Abstract

Aims: The aim of this work was to study the responses of Saccharomyces bayanus cells exposed to sub-lethal high-pressure homogenization (HPH) and determine whether the plasmatic membrane can sense HPH in the presence, or absence, of exogenous unsaturated fatty acids (UFAs) in the growth medium.Methods and Results: High-pressure homogenization damaged and caused the collapse of cell walls and membranes of a portion of cells; however, HPH did not significantly affect S. bayanus cell viability (less than 0.3 Log CFU ml-1). HPH strongly affected the membrane fatty acid (FA) composition by increasing the percentage of total UFA when compared with saturated fatty acids. The gene expression showed that the transcription of OLE1, ERG3, and ERG11 increased after HPH. The presence of exogenous UFA abolished HPH-induced effects on the OLE1 and ERG3 genes, increased the percentage of membrane lipids and decreased the expression of OLE1 and ERG3 within 30 min of treatment.Conclusion: The results suggest a key role for UFA in the microbial cell response to sub-lethal stress. In addition, these data provide insight into the molecular basis of the response of S. bayanus to this innovative technology.Significance and Impact of the Study: Elucidation of the mechanism of action for sub-lethal HPH will enable the utilization of this technology to modulate the starter performance at the industrial scale.

Highlights

High-pressure homogenization (HPH) is one of the most encouraging alternatives to the traditional thermal treatment used for food preservation and diversification
To verify the effect of HPH treatment on the viability of S. bayanus L951, cell load was recorded immediately after the treatment at 80 MPa and differences not exceeding 0.3 log CFU ml−1 were observed between the two samples (Figure 1)
Twenty-four hours after HPH treatment (Figure 2E), the cells appeared disaggregated and in active lysis when compared with control cells after 24 h of incubation

Summary

Introduction

High-pressure homogenization (HPH) is one of the most encouraging alternatives to the traditional thermal treatment used for food preservation and diversification. HPH treatment was recommended for bio-technological purposes aimed at enhancing the performance of certain lactic acid bacteria and yeasts (Tabanelli et al, 2012; Patrignani et al, 2013). HPH has been reported as a versatile approach for the modulation of the autolytic phenomena of starter tirage cultures used for the production of sparkling wines according to the traditional method. S. bayanus L951 subjected to 80 MPa before the preparation of a tirage solution accelerated its refermentation kinetics and enhanced its autolysis phenomena and modulated the volatile molecule profile of the sparkling wine obtained with this strain (Patrignani et al, 2013). According to Comuzzo et al (2015), HPH was a promising technique for inducing autolysis of wine yeasts

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