Transcriptome analysis of the thermotolerant yeast Kluyveromyces marxianus CCT 7735 under ethanol stress

Diniz, Raphael Hermano Santos; Villada, Juan C.; Alvim, Mariana Caroline Tocantins; Vidigal, Pedro Marcus Pereira; Vieira, Nívea Moreira; Lamas-Maceiras, Mónica; Cerdán, M. Esperanza; González-Siso, María-Isabel; Lahtvee, Petri‐Jaan; Silveira, Wendel Batista da

doi:10.1007/s00253-017-8432-0

Cited by 57 publications

(63 citation statements)

References 42 publications

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“…Our results suggested that this fraction was even smaller for Z. meyerae and P. burtonii because of their very low consumption of valine, leucine and phenylalanine and comparatively high production of the corresponding higher alcohols (Table 1 ), while it remained similar for K. marxianus , except for the phenylalanine/phenylethanol ratio which seemed to be higher. Since phenylethanol may be produced through the degradation of compounds arising from the pentose phosphate pathway, this observation is in accordance with the transcriptomic results reported in Diniz et al ( 2017 ). Indeed, the latter authors showed that the genes involved in the pentose phosphate pathway seemed to be overexpressed in the presence of 6% of ethanol.…”

Section: Discussionsupporting

confidence: 92%

“…The decline and premature death of K. marxianus during the sequential fermentation could be explained by its difficulty to overcome the ethanol increase and the impact on its plasmic membrane. Indeed, Diniz et al ( 2017 ) demonstrated that the expression of some gene-encoding enzymes related to unsaturated fatty acid and ergosterol biosynthesis decreased upon ethanol exposure, and free fatty acid and ergosterol measurements demonstrate that their content in K. marxianus did not change under this stress.…”

Section: Discussionmentioning

confidence: 99%

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Altered Fermentation Performances, Growth, and Metabolic Footprints Reveal Competition for Nutrients between Yeast Species Inoculated in Synthetic Grape Juice-Like Medium

et al. 2018

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The sequential inoculation of non-Saccharomyces yeasts and Saccharomyces cerevisiae in grape juice is becoming an increasingly popular practice to diversify wine styles and/or to obtain more complex wines with a peculiar microbial footprint. One of the main interactions is competition for nutrients, especially nitrogen sources, that directly impacts not only fermentation performance but also the production of aroma compounds. In order to better understand the interactions taking place between non-Saccharomyces yeasts and S. cerevisiae during alcoholic fermentation, sequential inoculations of three yeast species (Pichia burtonii, Kluyveromyces marxianus, Zygoascus meyerae) with S. cerevisiae were performed individually in a synthetic medium. Different species-dependent interactions were evidenced. Indeed, the three sequential inoculations resulted in three different behaviors in terms of growth. P. burtonii and Z. meyerae declined after the inoculation of S. cerevisiae which promptly outcompeted the other two species. However, while the presence of P. burtonii did not impact the fermentation kinetics of S. cerevisiae, that of Z. meyerae rendered the overall kinetics very slow and with no clear exponential phase. K. marxianus and S. cerevisiae both declined and became undetectable before fermentation completion. The results also demonstrated that yeasts differed in their preference for nitrogen sources. Unlike Z. meyerae and P. burtonii, K. marxianus appeared to be a competitor for S. cerevisiae (as evidenced by the uptake of ammonium and amino acids), thereby explaining the resulting stuck fermentation. Nevertheless, the results suggested that competition for other nutrients (probably vitamins) occurred during the sequential inoculation of Z. meyerae with S. cerevisiae. The metabolic footprint of the non-Saccharomyces yeasts determined after 48 h of fermentation remained until the end of fermentation and combined with that of S. cerevisiae. For instance, fermentations performed with K. marxianus were characterized by the formation of phenylethanol and phenylethyl acetate, while those performed with P. burtonii or Z. meyerae displayed higher production of isoamyl alcohol and ethyl esters. When considering sequential inoculation of yeasts, the nutritional requirements of the yeasts used should be carefully considered and adjusted accordingly. Finally, our chemical data suggests that the organoleptic properties of the wine are altered in a species specific manner.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Altered Fermentation Performances, Growth, and Metabolic Footprints Reveal Competition for Nutrients between Yeast Species Inoculated in Synthetic Grape Juice-Like Medium

et al. 2018

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“…In the case of unconventional thermotolerant yeast K. marxianus, however, there were only several reports of transcriptome analysis on yeast responses from different carbon source including glucose, inulin and xylose, or the tolerance to high temperature or ethanol stress. 18,69,70,71 To the best of our knowledge, genome-wide transcription analysis under the multiple inhibitors stress condition with elevated temperature (42 C) has not been reported for this yeast.…”

Section: Discussionmentioning

confidence: 99%

Transcriptomic analysis of thermotolerant yeastKluyveromyces marxianusin multiple inhibitors tolerance

Wang

Yang

et al. 2018

RSC Adv.

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During pretreatment of lignocellulosic biomass, toxic compounds were released and inhibited the growth and fermentation of microorganisms. Here the global transcriptional response of K. marxianus to multiple inhibitors including acetic acid, phenols, furfural and HMF, at 42 C, was studied, via RNA-seq technology.Genes involved in the glycolysis pathway, fatty acid metabolism, ergosterol metabolism and vitamin B6 and B1 metabolic process were enriched in the down-regulated gene set, while genes involved in TCA cycle, respiratory chain, ROS detoxification and transporter coding genes were enriched in the up-regulated gene set in response to the multiple inhibitors stress. Further real time-PCR results with three single inhibitor stress conditions showed that different transporters responded quite differently to different inhibitor stress. Coenzyme assay results showed that the level of NAD + was increased and both NADH/ NAD + and NADPH/NADP + ratio decreased. Furthermore, genes involved with transcription factors related to carbohydrate metabolism, sulfur amino acids metabolism, lipid metabolism or those directly involved in the transcriptional process were significantly regulated. Though belonging to different GO categories or KEGG pathway, many differentially expressed genes were enriched in maintaining the redox balance, NAD(P) + /NAD(P)H homeostasis or NAD + synthesis, energy production, and iron transportation or metabolism. These results suggest that engineering these aspects represents a possible strategy to develop more robust strains for industrial fermentation from cellulosic biomass.

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“…It has been shown that probiotic lactic acid bacteria may change their probiotic capacity when grown on different substrates (10). Furthermore, extensive transcriptomic changes have been described for K. marxianus under 6% ethanol stress (25). Even if this was not the aim of the referenced work, it can be speculated that these transcriptomic changes could affect probiotic features of ethanol-stressed yeasts.…”

Section: Discussionmentioning

confidence: 99%

A biorefinery concept for the production of fuel ethanol, probiotic yeast and whey protein from a by-product of the cheese industry

Pendón

Madeira

Romanin

et al. 2020

Preprint

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Agroindustrial by-products and residues can be transformed into valuable compounds in 24 biorefineries. Here we present a new concept: production of fuel ethanol, whey protein and 25 probiotic yeast from cheese whey. An initial screening under industrially relevant conditions, 26 involving thirty Kluyveromyces marxianus strains, was carried out using spot assays to 27 evaluate their capacity to grow on cheese whey or on whey permeate (100 g lactose/L), 28 under aerobic or anaerobic conditions, in the absence or presence of 5% ethanol, at pH 5.8 or 29 pH 2.5. The four best growing K. marxianus strains were selected and further evaluated in a 30 miniaturized industrial fermentation process using reconstituted whey permeate (100 g 31 lactose/L) with cell recycling (involving sulfuric acid treatment). After five consecutive 32 fermentation cycles, the ethanol yield on sugar reached 90% of the theoretical maximum in 33 the best cases, with 90% cell viability. Cells harvested at this point displayed probiotic 34 properties such as capacity to survive the passage through the gastrointestinal tract and 35 capacity to modulate innate immune response of intestinal epithelium, both in vitro. 36 Furthermore, the CIDCA 9121 strain was able to protect against histopathological damage in 37 an animal model of acute colitis. Our findings demonstrate that K. marxianus CIDCA 9121 38 is capable of efficiently fermenting the lactose present in whey permeate to ethanol and that 39 the remaining yeast biomass has probiotic properties, enabling an integrated process for the 40 obtainment of whey protein, fuel ethanol and probiotics from cheese whey. 41 42 2. Importance 43 Cheese whey is the liquid remaining following the precipitation and removal of milk casein 44 during cheese-making. This by-product represents about 85-95% of the milk volume and 45 retains 55% of milk nutrients so it can be exploited as a source of valuable end products. 46 However, at a global level around 50% of cheese whey is wasted, representing an important 47 environmental impact and indicating the need to develop alternative processes to recover 48 value. Kluyveromyces marxianus is capable of fermenting lactose, generally regarded as safe, 49 and has been explored separately as an ethanol producer and as a viable bioactive 50 microorganism. The significance of our research is to establish the proof of concept that a 51 biorefinery for fuel ethanol production using whey and K. marxianus can also be exploited to 52 obtain viable probiotic biomass, conferring an added value to the process and providing an 53 alternative to reduce environmental impact. 54 55 3 Introduction 56Whey production around the world is over 160 million tons per year and it is continuously 57 increasing (1). Whey is characterized by high ranges of biochemical oxygen demand (BOD) 58 and chemical oxygen demand (COD), 30-50 g/L and 60-80 g/L, respectively, mainly due to 59 its lactose content. In recent years, there has been a significant increase in alternative 60 p...

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Transcriptome analysis of the thermotolerant yeast Kluyveromyces marxianus CCT 7735 under ethanol stress

Cited by 57 publications

References 42 publications

Altered Fermentation Performances, Growth, and Metabolic Footprints Reveal Competition for Nutrients between Yeast Species Inoculated in Synthetic Grape Juice-Like Medium

Altered Fermentation Performances, Growth, and Metabolic Footprints Reveal Competition for Nutrients between Yeast Species Inoculated in Synthetic Grape Juice-Like Medium

Transcriptomic analysis of thermotolerant yeastKluyveromyces marxianusin multiple inhibitors tolerance

A biorefinery concept for the production of fuel ethanol, probiotic yeast and whey protein from a by-product of the cheese industry

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