Phenotypic landscape of non-conventional yeast species for different stress tolerance traits desirable in bioethanol fermentation

Mukherjee, Vaskar; Radecka, Dorota; Aerts, Guido; Verstrepen, Kevin J.; Lievens, Bart; Thevelein, Johan M.

doi:10.1186/s13068-017-0899-5

Cited by 83 publications

(62 citation statements)

References 97 publications

(115 reference statements)

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“…These results are similar to those found in the literature [22], which report the growth of the Basidiomycete Phanerochaete chrysosporium in the presence of ethanol concentrations of 12.2%. The level of ethanol tolerance of T. hirsuta obtained in this work is similar to that of Saccharomyces cerevisiae, which possesses a high tolerance to ethanol (concentrations up to 14%) and is traditionally used for the production of alcoholic beverages and bioethanol [54,55].…”

Section: Tolerance To Ethanolsupporting

confidence: 54%

Consolidated Bioprocess for Bioethanol Production from Raw Flour of Brosimum alicastrum Seeds Using the Native Strain of Trametes hirsuta Bm-2

et al. 2019

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Consolidated bioprocessing (CBP), which integrates biological pretreatment, enzyme production, saccharification, and fermentation, is a promising operational strategy for cost-effective ethanol production from biomass. In this study, the use of a native strain of Trametes hirsuta (Bm-2) was evaluated for bioethanol production from Brosimum alicastrum in a CBP. The raw seed flour obtained from the ramon tree contained 61% of starch, indicating its potential as a raw material for bioethanol production. Quantitative assays revealed that the Bm-2 strain produced the amylase enzyme with activity of 193.85 U/mL. The Bm-2 strain showed high tolerance to ethanol stress and was capable of directly producing ethanol from raw flour at a concentration of 13 g/L, with a production yield of 123.4 mL/kg flour. This study demonstrates the potential of T. hirsuta Bm-2 for starch-based ethanol production in a consolidated bioprocess to be implemented in the biofuel industry. The residual biomass after fermentation showed an average protein content of 22.5%, suggesting that it could also be considered as a valuable biorefinery co-product for animal feeding.Microorganisms 2019, 7, 483 2 of 16 use bioethanol as their main source of fuel. Ethanol blends vary depending on the country, containing from as low as 5% (E5) to 100% bioethanol (E100) [4][5][6][7].The growing global demand for bioethanol requires the use of alternative sources of raw materials to complement sugar cane and cornstarch, which are the main raw materials used to produce it. Starch crops are widely used for bioethanol production because of their worldwide availability, easy conversion, and high ethanol yield. These raw materials include cereals (60%-80% starch), tubers and roots (60%-90%), legumes (25%-50%), and green and immature fruits (up to 70% starch) [2].Conventionally, ethanol production from starch consists of several stages. Starch is subjected to a gelatinization process followed by a liquefaction step where starch is converted to dextrins and smaller molecules by the action of bacterial thermostable amylases at high temperatures (95-105 • C) and pH values between 6 and 6.5. This step is followed by saccharification. The liquefied starch is cooled, pH is adjusted to 4-4.5, temperatures to 60-65 • C, and a fungal glucoamylase is added to hydrolyze the oligosaccharides to glucose. The liquefaction and saccharification stages represent about 40%-50% of the total energy used during starch-based ethanol production [8][9][10].Owing to this technical complexity and the economic implications of this approach, other biological alternatives have been investigated, such as simultaneous saccharification and fermentation (SSF) and consolidated bioprocessing (CBP). The latter is a promising strategy for effective ethanol production, since it employs only one type of microorganism that is capable of both producing the enzymes to hydrolyze the biomass and converting sugars into ethanol [11,12]. This strategy has the potential of lowering the cost and enhancing the efficie...

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Section: Tolerance To Ethanolsupporting

confidence: 54%

Consolidated Bioprocess for Bioethanol Production from Raw Flour of Brosimum alicastrum Seeds Using the Native Strain of Trametes hirsuta Bm-2

et al. 2019

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“…M. pulcherrima was termed osmophilic previously, when researchers demonstrated growth at an a w of 0.88, better than six other yeast isolated from grapes, including the oleaginous yeast R. glutinis with an a w threshold of 0.94 (Rousseau & Donèche, ); and even survived at 70% (w/v) glucose loading (a w < 0.82; Mukherjee et al, ). High osmotolerance is known for Candida species (Rousseau & Donèche, ; Sipiczki, ; Zhuge et al, ) in close phylogenetic proximity to M. pulcherrima (Masneuf‐Pomarede, Bely, Marullo, & Albertin, ).…”

Section: Resultsmentioning

confidence: 99%

Achieving a high‐density oleaginous yeast culture: Comparison of four processing strategies using Metschnikowia pulcherrima

Abeln

Chuck

2019

Biotech & Bioengineering

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Microbial lipids have the potential to displace terrestrial oils for fuel, value chemical, and food production, curbing the growth in tropical oil plantations and helping to reduce deforestation. However, commercialization remains elusive partly due to the lack of suitably robust organisms and their low lipid productivity. Extremely high cell densities in oleaginous cultures are needed to increase reaction rates, reduce reactor volume, and facilitate downstream processing. In this investigation, the oleaginous yeast Metschnikowia pulcherrima, a known antimicrobial producer, was cultured using four different processing strategies to achieve high cell densities and gain suitable lipid productivity. In batch mode, the yeast demonstrated lipid contents more than 40% (w/w) under high osmotic pressure. In fed-batch mode, however, high-lipid titers were prevented through inhibition above 70.0 g L −1 yeast biomass. Highly promising were a semi-continuous and continuous mode with cell recycle where cell densities of up to 122.6 g L −1 and maximum lipid production rates of 0.37 g L −1 h −1 (daily average), a nearly two-fold increase from the batch, were achieved. The findings demonstrate the importance of considering multiple fermentation modes to achieve high-density oleaginous yeast cultures generally and indicate the limitations of processing these organisms under the extreme conditions necessary for economic lipid production. K E Y W O R D Scontinuous, fed-batch, high cell density, microbial lipids, oleaginous yeast, semi-continuous

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“…Ethanol tolerance is one widely sought‐after characteristic for new brewing yeasts (Mukherjee et al, ; Osburn et al, ; Ruyters et al, ). This can be favoured by using inhibitory ethanol concentrations in one or more steps during the isolation procedure.…”

Section: Isolation and Brewing Potential Of Non‐saccharomyces Sppmentioning

confidence: 99%

Bioprospecting for brewers: Exploiting natural diversity for naturally diverse beers

Cubillos

Gibson

Grijalva‐Vallejos

et al. 2019

Yeast

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The burgeoning interest in archaic, traditional, and novel beer styles has coincided with a growing appreciation of the role of yeasts in determining beer character as well as a better understanding of the ecology and biogeography of yeasts. Multiple studies in recent years have highlighted the potential of wild Saccharomyces and non-Saccharomyces yeasts for production of beers with novel flavour profiles and other desirable properties. Yeasts isolated from spontaneously fermented beers as well as from other food systems (wine, bread, and kombucha) have shown promise for brewing application, and there is evidence that such cross-system transfers have occurred naturally in the past. We review here the available literature pertaining to the use of nonconventional yeasts in brewing, with a focus on the origins of these yeasts, including methods of isolation. Practical aspects of utilizing nondomesticated yeasts are discussed, and modern methods to facilitate discovery of yeasts with brewing potential are highlighted.

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Phenotypic landscape of non-conventional yeast species for different stress tolerance traits desirable in bioethanol fermentation

Cited by 83 publications

References 97 publications

Consolidated Bioprocess for Bioethanol Production from Raw Flour of Brosimum alicastrum Seeds Using the Native Strain of Trametes hirsuta Bm-2

Consolidated Bioprocess for Bioethanol Production from Raw Flour of Brosimum alicastrum Seeds Using the Native Strain of Trametes hirsuta Bm-2

Achieving a high‐density oleaginous yeast culture: Comparison of four processing strategies using Metschnikowia pulcherrima

Bioprospecting for brewers: Exploiting natural diversity for naturally diverse beers

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