Selection of thermotolerant Saccharomyces cerevisiae for high temperature ethanol production from molasses and increasing ethanol production by strain improvement

Pattanakittivorakul, Sornsiri; Lertwattanasakul, Noppon; Yamada, Mamoru; Limtong, Savitree

doi:10.1007/s10482-019-01230-6

Cited by 38 publications

(16 citation statements)

References 46 publications

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“…These results fit well with the microbiological observation that underlined the stress exerted by high temperatures on LAB activity. The sensitivity of S. cerevisiae to high-fermentation temperature was recently confirmed by Pattanakittivorakul et al (2019) who characterized some species of yeast in order to improve bioethanol production. Schwinn et al (2019) observed differences in volatile accumulation by S. cerevisiae when increasing the temperature from 14 to 19°C.…”

Section: Discussionmentioning

confidence: 86%

Impact of different temperature profiles on simultaneous yeast and bacteria fermentation

2020

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Purpose: The role of fermentation temperature was studied for its impact on the evolution of malolactic fermentation performed by simultaneous inoculum of yeast and bacteria in grape must. Results were discussed considering the different fermentative kinetics and the composition of obtained wines. Methods: Two strains of bacteria belonging to the O. oeni and L. plantarum species were inoculated 24 h after the beginning of the alcoholic fermentation in 2 grape musts having different acidic and sugar profiles. Fermentations were conducted at 3 different temperature profiles (16/22°C in 3 days, 18/24°C in 3 days, 22/32°C in 5 days). Evolution of microbiota was followed by flow cytometry and plate count. Chemical analysis of grape musts and wines were performed by instrumental approaches (FT-IR, enzymatic quantification of malic acid, GC-MS). Results: L. plantarum resulted more efficient in malic acid consumption in the entire set of tests. These results are unexpected because, generally, Lactobacillus has been reported to be more sensitive to an oenological environment than O. oeni. In our experiments, O. oeni resulted inhibited by the highest fermentation temperature profile, causing incomplete malic acid degradation. Similarly, S. cerevisiae showed a higher sensitivity to environmental limiting factors in respect to what is generally known. Differences in the chemical composition of wines were observed in relation to the bacteria strain and the temperature profile. However, the statistical treatment of data identified temperature as the main variable able to influence the features of wines. Conclusions: Simultaneous inoculum of yeast and bacteria in grape must is an alternative approach in the management of malolactic fermentation which showed some interesting features. However, it is necessary to consider that the dynamics of the microbial population are different to that observed in traditional winemaking and the environmental variables act against the microorganisms in a peculiar, and in certain cases unexpected, way.

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Section: Discussionmentioning

confidence: 86%

Impact of different temperature profiles on simultaneous yeast and bacteria fermentation

2020

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“…Hence, tools such as the statistical design of experiment (DoE) allow investigating the effect of several operational factors as well as their interactions on the overall process while considerably reducing the number of experimental tests [20]. For instance, a central composite design coupled with response surface methodology (CCD-RSM) represents a powerful and effective statistical tool that could commonly be used for the optimization of biotechnological processes such as fermentation [19,21,22]. Once developed, the CCD-RSM can be used to predict a process output, while imposing specific constraints based on economical and technical aspects.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Yeast, Sugar and Nutrient Concentrations for High Ethanol Production Rate Using Industrial Sugar Beet Molasses and Response Surface Methodology

2021

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Among the various agro-industrial by-products, sugar beet molasses produced by sugar refineries appear as a potential feedstock for ethanol production through yeast fermentation. A response surface methodology (RSM) was developed to better understand the effect of three process parameters (concentration of nutrient, yeast and initial sugar) on the ethanol productivity using diluted sugar beet molasses and Saccharomyces cerevisiae yeast. The first set of experiments performed at lab-scale indicated that the addition of 4 g/L of nutrient combined with a minimum of 0.2 g/L of yeast as well as a sugar concentration lower than 225 g/L was required to achieve high ethanol productivities (<15 g/L/d). The optimization allowed to considerably reduce the amount of yeast initially introduced in the fermentation substrate while still maximizing both ethanol productivity and yield process responses. Finally, scale-up assays were carried out in 7.5 and 100 L bioreactors using the optimal conditions: 150 g/L of initial sugar concentration, 0.27 g/L of yeast and 4 g/L of nutrient. Within 48 h of incubation, up to 65 g/L of ethanol were produced for both scales, corresponding to an average ethanol yield and sugar utilization rate of 82% and 85%, respectively. The results obtained in this study highlight the use of sugar beet molasses as a low-cost food residue for the sustainable production of bioethanol.

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“…With that, the use of e-beam for sterilisation of the substrate could also make it possible to use more productive yeast strains in the fermentation, such as the thermotolerant strains of S. cerevisiae described by Pattanakittivorakul et al (2019), which show extremely high ethanol production at 40 ˚C, in addition to tolerating high gravity fermentation and high concentrations of furfural, HMF and acetic acid.…”

Section: Resultsmentioning

confidence: 99%

Sterilisation of Wort from Sugarcane Molasses by Electron Beam for Bioethanol Production

Calegari¹,

Silva²,

Gomes³

et al. 2021

Preprint

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The presence of microbial contamination in the wort during the fermentation process results in damages of billions of dollars per year all around the world and promotes the industry dependence of chemicals and antibiotics to control the contamination. For these reasons, this study aimed to use the electron beam to sterilise wort from sugarcane molasses and investigate its bioethanol fermentation. Five treatments (T0 – T4) were carried out using ionizing doses of radiation through the electron accelerator: (0, 10, 20, 40, and 80 kGy) and a positive control (T5-steam by autoclave) were performed. It was evaluated total mesophiles, total bacteria, sugars, phenolics, flavonoids, 5-hidroximetylfurfural, and Furfural. After the irradiation process, it was conducted an alcoholic fermentation assay using baker’s yeast Saccharomyces cerevisiae. It was not observed inversion of sugars and formation of the inhibitory by-products flavonoids, furfural, and 5-hidroximetylfurfural, with exception of the phenolic compounds. Only T4 and T5 were able to sterilise the wort. However, T3 was able to eliminate > 99.99% of the microorganisms. In the fermentation T2 promoted the best ethanol yield and productivity among the irradiated treatments, evidencing the possibility of electron beam use in the wort treatment prior to fermentation which may allow a reduction in losses caused by microbial contamination, besides the possibility of promoting fermentation yield and productivity increase. The operation cost for applying the e-beam with a dose of 20 kGy in a standard ethanol plant was estimated at US$ 0.014 per m3 of wort.

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Selection of thermotolerant Saccharomyces cerevisiae for high temperature ethanol production from molasses and increasing ethanol production by strain improvement

Cited by 38 publications

References 46 publications

Impact of different temperature profiles on simultaneous yeast and bacteria fermentation

Impact of different temperature profiles on simultaneous yeast and bacteria fermentation

Optimization of Yeast, Sugar and Nutrient Concentrations for High Ethanol Production Rate Using Industrial Sugar Beet Molasses and Response Surface Methodology

Sterilisation of Wort from Sugarcane Molasses by Electron Beam for Bioethanol Production

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