The Plasma Membrane at the Cornerstone Between Flexibility and Adaptability: Implications for Saccharomyces cerevisiae as a Cell Factory

Ferraz, Luís; Sauer, Michael; Sousa, Maria João; Branduardi, Paola

doi:10.3389/fmicb.2021.715891

Cited by 12 publications

(5 citation statements)

References 94 publications

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“…9b). In such an anaerobic/micro-aerophilic environment, the accumulated ethanol permeates into yeast cells, denatures cellular proteins, hydrophobically inhibits glycolysis, and disintegrates the cell membrane's phospholipid lining (Ferraz et al 2021). Additionally, the substrate and oxygen limitation may result in cell death (Pauline 2013).…”

Section: Bio-ethanol Fermentation: the Process Challenges Operational...mentioning

confidence: 99%

Analyses of challenges faced during the production of amylolytic enzymes and bio-ethanol using left-over cooked-rice, and rice unfit for human consumption

2023

ajom

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Rice-based enzyme and alcohol production bio-processes using fungi have been explored for years, but they have suffered from the long-pending predicament of presenting their challenges. Currently, major agricultural countries have been resorting to the usage of surplus first-generation biomass sources in bio-refineries. The present lab-scale work proposes, analyzes, and presents the scale-up challenges of such processes while using a novel mixture of left-over cooked rice and market-rejected rice grains. Fractionated rice grains were used as the substrates for enzyme production. Alpha-amylase (365 IU/mL) was produced by employing Aspergillus oryzae 113 ATCC [9102], while glucoamylase (96 IU/mL) was produced by employing Aspergillus niger A1143 NRRL3 [DSM2466] in separate 144-h-long bio-processes. A mixture of left-over cooked rice and rice grains was sequentially saccharified using the produced enzymes, showing a cumulative 51.66% saccharification. Fermentation of the saccharified hydrolysate using Saccharomyces cerevisiae yielded 59.2 g/L bio-ethanol (starch-conversion: 63.3%) with 190-proof purity (95% v/v). The impact of the enzyme/bio-ethanol production on the coefficients of fungal biomass yield (Yx/s, Yx/O2) and maintenance (msx, mO2x), the rates of specific growth (μ) and substrate uptake (SUR) were analyzed individually. A fundamental techno-economic analysis of the entire process has been presented.

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Section: Bio-ethanol Fermentation: the Process Challenges Operational...mentioning

confidence: 99%

Analyses of challenges faced during the production of amylolytic enzymes and bio-ethanol using left-over cooked-rice, and rice unfit for human consumption

2023

ajom

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“…However, these studies do not focus on yeast cell-plasma membranes and their fluidity or rigidity in the context of viability. Yeast cells respond to environmental changes, such as nutrient deficiency, metabolite accumulation, temperature fluctuations, or pH maintenance, by adapting the plasma membrane structures [14]. An acidic cell growth environment lowers the intracellular pH value (ICP) in the cytosol, which activates the ATPase [15].…”

Section: Introductionmentioning

confidence: 99%

Quantification methods of determining brewer’s and pharmaceutical yeast cell viability: accuracy and impact of nanoparticles

et al. 2023

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For industrial processes, a fast, precise, and reliable method of determining the physiological state of yeast cells, especially viability, is essential. However, an increasing number of processes use magnetic nanoparticles (MNPs) for yeast cell manipulation, but their impact on yeast cell viability and the assay itself is unclear. This study tested the viability of Saccharomyces pastorianus ssp. carlsbergensis and Pichia pastoris by comparing traditional colourimetric, high-throughput, and growth assays with membrane fluidity. Results showed that methylene blue staining is only reliable for S. pastorianus cells with good viability, being erroneous in low viability (R2 = 0.945; $$\widehat{\sigma }$$ σ ^ = 5.78%). In comparison, the fluorescence microscopy–based assay of S. pastorianus demonstrated a coefficient of determination of R2 = 0.991 at $$\alpha =0$$ α = 0 ($$\widehat{\sigma }$$ σ ^ = 2.50%) and flow cytometric viability determination using carboxyfluorescein diacetate (CFDA), enabling high-throughput analysis of representative cell numbers; R2 = 0.972 ($$\alpha =0$$ α = 0 ; $$\widehat{\sigma }$$ σ ^ = 3.89%). Membrane fluidity resulted in a non-linear relationship with the viability of the yeast cells ($$\alpha \ne 0$$ α ≠ 0 ). We also determined similar results using P. pastoris yeast. In addition, we demonstrated that MNPs affected methylene blue staining by overestimating viability. The random forest model has been shown to be a precise method for classifying nanoparticles and yeast cells and viability differentiation in flow cytometry by using CFDA. Moreover, CFDA and membrane fluidity revealed precise results for both yeasts, also in the presence of nanoparticles, enabling fast and reliable determination of viability in many experiments using MNPs for yeast cell manipulation or separation.

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“…In this work, we are particularly interested in organic acid stress of yeast cells and how membrane composition, in terms of ergosterol content, relates to stress tolerance. The impact of individual lipid species on the plasma membrane physicochemical properties is difficult to predict (Ferraz et al, 2021). Nevertheless, a more rigid and less permeable membrane is likely to reduce the diffusion of acids into the cell and, therefore, likely to increase resistance toward the acids.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, when organic acids are produced by yeast and high titers are reached, the interaction of the accumulating products with the plasma membrane might become an additional stress factor (Jezierska & Van Bogaert, 2017). The plasma membrane plays a key role in these processes, acting as a selective gate, controlling the flux of compounds into and out of the cell (Ferraz et al, 2021). As such, the plasma membrane has been proven to be an important target for stress adaptation when designing strategies for the development of versatile, robust, and efficient cell factories ready to tackle the harshness of industrial processes while delivering high yield, titer, and productivity (Russell et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

Impact of ergosterol content on acetic and lactic acids toxicity to Saccharomyces cerevisiae

Ferraz

Vorauer-Uhl

Sauer

et al. 2022

Yeast

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Organic acid stress often represents a major hurdle in industrial bio‐based microbial processes. Organic acids can be released from lignocellulosic feedstocks pretreatment and can also be desirable products obtained by microbial fermentation with applications in different industrial sectors. Yeasts are prominent cell factories. However, the presence of organic acids can compromise yeast metabolism, impairing fermentation performances and limiting the economic feasibility of the processes. Plasma membrane remodeling is deeply involved in yeast tolerance to organic acids, but the detailed mechanisms and potentials of this phenomenon remain largely to be studied and exploited. We investigated the impact of ergosterol on Saccharomyces cerevisiae tolerance against organic acid stress by coupling in vitro and in vivo assays. In the in vitro assay, synthetic lipid vesicles were prepared containing different concentrations of ergosterol. We observed changes in organic acids diffusion through the membrane as a function of ergosterol content. Then, we extended our approach in vivo, engineering S. cerevisiae with the aim of changing the ergosterol content of cells. We focused on ECM22, an important transcription factor, involved in the regulation of ergosterol biosynthesis. The overexpression of ECM22 was sufficient to increase ergosterol levels in S. cerevisiae, resulting in an enhanced tolerance toward lactic acid stress. In this work we propose an in vitro approach, using synthetic lipid vesicles, as a complementary method to be used when studying the impact of the plasma membrane lipid composition on the diffusion of organic acids.

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The Plasma Membrane at the Cornerstone Between Flexibility and Adaptability: Implications for Saccharomyces cerevisiae as a Cell Factory

Cited by 12 publications

References 94 publications

Analyses of challenges faced during the production of amylolytic enzymes and bio-ethanol using left-over cooked-rice, and rice unfit for human consumption

Analyses of challenges faced during the production of amylolytic enzymes and bio-ethanol using left-over cooked-rice, and rice unfit for human consumption

Quantification methods of determining brewer’s and pharmaceutical yeast cell viability: accuracy and impact of nanoparticles

Impact of ergosterol content on acetic and lactic acids toxicity to Saccharomyces cerevisiae

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