scholarly journals Robustness and Ethanol Production of Industrial Strains of Saccharomyces cerevisiae Using Different Sugarcane Bagasse Hydrolysates

2019 ◽  
Vol 7 (1) ◽  
pp. 23 ◽  
Author(s):  
Vanessa S. Teixeira ◽  
Suéllen P. H. Azambuja ◽  
Priscila H. Carvalho ◽  
Fátima A. A. Costa ◽  
Patricia R. Kitaka ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Sugarcane Bagasse ◽  
Ethanol Yield ◽  
Raw Materials ◽  
Fermentation Inhibitors ◽  
Severe Condition ◽  
Inhibitor Tolerance ◽  
Industrial Strains ◽  
Materials Used

Sugarcane bagasse is one of the main lignocellulosic raw materials used for the production of second-generation ethanol. Technological studies on fermentation processes have focused on the search for and development of more robust microorganisms that are able to produce bioethanol efficiently and are resistant to the main fermentation inhibitors. The purpose of this study was to evaluate the robustness and ethanol production of industrial strains of Saccharomyces cerevisiae using acid, alkaline, and enzymatic sugarcane bagasse hydrolysates. Hydrolysis was carried out to release fermentable sugars from sugarcane bagasse. Fermentations were performed in shake flasks containing sugarcane hydrolysates supplemented with 150 g L−1 glucose to evaluate the kinetic parameters of the reaction. Inhibitor tolerance was evaluated by incubating cells with different concentrations of inhibitors in 96-well plates. The biomass yield on substrate, ethanol yield on substrate, and ethanol productivity of the six strains were higher in 0.5% acid, 0.5% alkaline, and enzymatic hydrolysates (i.e., under milder conditions). The SA-1 (Santa Adélia-1) strain had a better performance in comparison with the other strains for its ability to produce ethanol in a very severe condition (7% acid hydrolysis) and for its robustness in growing at several inhibitor concentrations.

scholarly journals Simultaneous saccharification and co-fermentation with a thermotolerant Saccharomyces cerevisiae to produce ethanol from sugarcane bagasse under high temperature conditions

BioResources ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. 1358-1372
Author(s):  
Wei-Lin Tu ◽  
Tien-Yang Ma ◽  
Chung-Mao Ou ◽  
Gia-Luen Guo ◽  
Yu Chao
Keyword(s):  
Saccharomyces Cerevisiae ◽  
High Temperature ◽  
Ethanol Production ◽  
Sugarcane Bagasse ◽  
Ethanol Yield ◽  
Xylose Utilization ◽  
Inhibitor Tolerance ◽  
Temperature Conditions ◽  
Xylose Uptake ◽  
Simultaneous Saccharification

Lignocellulosic ethanol production at high temperature offers advantages such as the decrease of contamination risk and cooling cost. Recombinant xylose-fermenting Saccharomyces cerevisiae has been considered a promising strain for ethanol production from lignocellulose for its high inhibitor tolerance and superior capability to ferment glucose and xylose into ethanol. To improve the ethanolic fermentation by xylose at high temperature, the strain YY5A was subjected to the ethyl methanesulfonate (EMS) mutagenesis. A mutant strain T5 was selected from the EMS-treated cultures to produce ethanol. However, the xylose uptake by T5 was severely inhibited by the high ethanol concentration during the co-fermentation in defined YPDX medium at 40 °C. In this study, the simultaneous saccharification and co-fermentation (SSCF) and the separate hydrolysis and co-fermentation (SHCF) processes of sugarcane bagasse were assessed to solve this problem. The xylose utilization by T5 was remarkably improved using the SSCF process compared to the SHCF process. For the SHCF and SSCF processes, 48% and 99% of the xylose in the hydrolysate was consumed at 40 °C, respectively. The ethanol yield was enhanced by the SSCF process. The ethanol production can reach to 36.0 g/L using this process under high-temperature conditions.

scholarly journals Bioethanol Production by Using Detoxified Sugarcane Bagasse Hydrolysate and Adapted Culture of Candida tropicalis

2016 ◽  
Vol 2 (1) ◽  
pp. 1-12
Author(s):  
Inda Setyawati ◽  
Laksmi Ambarsari ◽  
Siti Nur'aeni ◽  
Suryani Suryani ◽  
Puspa Julistia Puspita ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Sugarcane Bagasse ◽  
Ethanol Yield ◽  
Renewable Resource ◽  
Bioethanol Production ◽  
Fermentation Inhibitors ◽  
Renewable Materials ◽  
Promising Alternative ◽  
Fermentation Time ◽  
Sugarcane Bagasse Hydrolysate

Ethanol is considered as the most promising alternative fuel, since it can be produced from a variety of agriculturally-based renewable materials, such as sugarcane bagasse. Lignocellulose as a major component of sugarcane bagasse is considered as an attractive renewable resource for ethanol production due to its great availability and relatively low cost. The major problem of lignocellulose is caused by its need for treatment to be hydrolyzed to simple sugar before being used for bioethanol production. However, pretreatment using acid as hydrolyzing agent creates some inhibitor compounds that reduce ethanol production because these compounds are potential fermentation inhibitors and affect the growth rate of the yeast. Reduction of these by-products requires a conditioning (detoxification and culture starter adaptation). Thus, the aim of this study was to evaluate bioethanol production by fermentation with and without detoxified sugarcane bagasse acid hydrolysate using adapted and non-adapted culture of C. tropicalis. According to this study, the highest ethanol amount was obtained about 0.43 % (v/v) with an ethanol yield of 2.51 % and theoretical yield of 4.92 % by fermentation of sugarcane bagasse hydrolysate with detoxification using the adapted strain of C. tropicalis at 72 hours fermentation time. Furthermore, the addition of 3 % glucose as co-substrate on detoxified-hydrolysate media only achieved the highest ethanol concentration 0.21 % after 24 hours fermentation with the ethanol yield 0.69 % and theoretical ethanol yield 1.35 %, thus it can be concluded that the addition of glucose could not increase the ethanol production.

scholarly journals Ethanol production by Pichia stipitis immobilized on sugarcane bagasse

Bioethanol ◽  
2016 ◽  
Vol 2 (1) ◽  
Author(s):  
BS Yñiguez-Balderas ◽  
B Ortiz-Muñiz ◽  
J Gómez-Rodríguez ◽  
B Gutierrez-Rivera ◽  
MG Aguilar-Uscanga
Keyword(s):  
Ethanol Production ◽  
Sugarcane Bagasse ◽  
Ethanol Yield ◽  
Raw Materials ◽  
Pichia Stipitis ◽  
Inoculum Size ◽  
Process Efficiency ◽  
Immobilized Cell ◽  
Production Technologies ◽  
Gab Model

AbstractThe search for new ethanol production technologies is due to this biofuel being a renewable and environmentally friendly option. Immobilized cell systems for ethanol production have been studied; however, the phenomenon involved in cell sorption on raw materials has been poorly explored. Therefore, this work evaluates P. stipitis immobilization on sugarcane bagasse pretreated with sulphuric acid, as well as ethanol production in batch culture. The results obtained showed that the Guggenheim-Anderson-de Boer (GAB) model explained the sorption phenomenon. The selected inoculum size for immobilization was the same as the monolayer sorption capability (1.17 gl-1). Using 1:100 g ml- 1 solid-liquid ratio, at 250 rpm, ethanol yield and productivity of 0.404 gg-1 glucose and 0.41 gl-1h-1 were obtained, respectively. The immobilized systems were stable for up to twenty-five repeated batches (36 h each). Ethanol production was increased from the first to the twenty-fifth batch (18.1 and 24.7 gl-1 ethanol). The use of complex media, such as molasses “B” or sugarcane hydrolyzates, caused an increase in process efficiency 2.4 and 1.8-fold respectively, compared with free cells systems. Biotechnological ethanol production from lignocellulosic hydrolyzates could be improved by the use of the immobilization cell sorption on pre-treated raw materials.

scholarly journals Flocculation Causes Inhibitor Tolerance in Saccharomyces cerevisiae for Second-Generation Bioethanol Production

2014 ◽  
Vol 80 (22) ◽  
pp. 6908-6918 ◽  
Author(s):  
Johan O. Westman ◽  
Valeria Mapelli ◽  
Mohammad J. Taherzadeh ◽  
Carl Johan Franzén
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Second Generation ◽  
Raw Materials ◽  
Defined Medium ◽  
Bioethanol Production ◽  
Dilute Acid ◽  
Fermentation Inhibitors ◽  
Inhibitor Tolerance ◽  
Content Type ◽  
Second Generation Bioethanol

ABSTRACTYeast has long been considered the microorganism of choice for second-generation bioethanol production due to its fermentative capacity and ethanol tolerance. However, tolerance toward inhibitors derived from lignocellulosic materials is still an issue. Flocculating yeast strains often perform relatively well in inhibitory media, but inhibitor tolerance has never been clearly linked to the actual flocculation abilityper se. In this study, variants of the flocculation geneFLO1were transformed into the genome of the nonflocculating laboratory yeast strainSaccharomyces cerevisiaeCEN.PK 113-7D. Three mutants with distinct differences in flocculation properties were isolated and characterized. The degree of flocculation and hydrophobicity of the cells were correlated to the length of the gene variant. The effect of different strength of flocculation on the fermentation performance of the strains was studied in defined medium with or without fermentation inhibitors, as well as in media based on dilute acid spruce hydrolysate. Strong flocculation aided against the readily convertible inhibitor furfural but not against less convertible inhibitors such as carboxylic acids. During fermentation of dilute acid spruce hydrolysate, the most strongly flocculating mutant with dense cell flocs showed significantly faster sugar consumption. The modified strain with the weakest flocculation showed a hexose consumption profile similar to the untransformed strain. These findings may explain why flocculation has evolved as a stress response and can find application in fermentation-based biorefinery processes on lignocellulosic raw materials.

scholarly journals Effects of Ultrasound on Fermentation of Glucose to Ethanol by Saccharomyces cerevisiae

Fermentation ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 16 ◽  
Author(s):  
Luis Huezo ◽  
Ajay Shah ◽  
Frederick Michel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mass Transfer ◽  
Glucose Uptake ◽  
Ethanol Production ◽  
Ethanol Yield ◽  
Biofuel Production ◽  
Inhibitory Effects ◽  
Negative Effects ◽  
Intraparticle Mass Transfer ◽  
Improve Mass Transfer

Previous studies have shown that pretreatment of corn slurries using ultrasound improves starch release and ethanol yield during biofuel production. However, studies on its effects on the mass transfer of substrates and products during fermentation have shown that it can have both beneficial and inhibitory effects. In this study, the effects of ultrasound on mass transfer limitations during fermentation were examined. Calculation of the external and intraparticle observable moduli under a range of conditions indicate that no external or intraparticle mass transfer limitations should exist for the mass transfer of glucose, ethanol, or carbon dioxide. Fermentations of glucose to ethanol using Saccharomyces cerevisiae were conducted at different ultrasound intensities to examine its effects on glucose uptake, ethanol production, and yeast population and viability. Four treatments were compared: direct ultrasound at intensities of 23 and 32 W/L, indirect ultrasound (1.4 W/L), and no-ultrasound. Direct and indirect ultrasound had negative effects on yeast performance and viability, and reduced the rates of glucose uptake and ethanol production. These results indicate that ultrasound during fermentation, at the levels applied, is inhibitory and not expected to improve mass transfer limitations.

scholarly journals Incorporation of sugarcane bagasse ash waste as an alternative raw material for red ceramic

Cerâmica ◽  
2013 ◽  
Vol 59 (351) ◽  
pp. 473-480 ◽  
Author(s):  
K. C. P. Faria ◽  
J. N. F. Holanda
Keyword(s):  
Sugarcane Bagasse ◽  
Raw Materials ◽  
Phase Evolution ◽  
Linear Shrinkage ◽  
Raw Material ◽  
Partial Replacement ◽  
Clay Material ◽  
Natural Clay ◽  
Materials Used ◽  
Sugarcane Industry

The sugarcane industry generates huge amounts of sugarcane bagasse ashes (SCBA). This work investigates the incorporation of a SCBA waste as an alternative raw material into a clay body, replacing natural clay material by up to 20 wt.%. Clay ceramic pieces were produced by uniaxial pressing and fired at temperatures varying from 700 to 1100 ºC. The technological properties of the clay ceramic pieces (linear shrinkage, apparent density, water absorption, and tensile strength) as function of the firing temperature and waste addition are investigated. The phase evolution during firing was followed by X-ray diffraction. The results showed that the SCBA waste could be incorporated into red ceramics (bricks and roofing tiles) in partial replacement for natural clay material. These results confirm the feasibility of valorisation of SCBA waste to produce red ceramic. This use of SCBA can also contribute greatly to reducing the environmental problems of the sugarcane industry, and also save the sources of natural raw materials used in the ceramic industry.

scholarly journals Direct Ethanol Production from Lignocellulosic Sugars and Sugarcane Bagasse by a RecombinantTrichoderma reeseiStrain HJ48

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Jun Huang ◽  
Dong Chen ◽  
Yutuo Wei ◽  
Qingyan Wang ◽  
Zhenchong Li ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Trichoderma Reesei ◽  
Sugarcane Bagasse ◽  
Consolidated Bioprocessing ◽  
Ethanol Yield ◽  
Genome Shuffling ◽  
Wild Type ◽  
Mutant Population ◽  
Ethanol Resistance ◽  
Lignocellulosic Sugars

Trichoderma reeseican be considered as a candidate for consolidated bioprocessing (CBP) microorganism. However, its ethanol yield needs to be improved significantly. Here the ethanol production ofT. reeseiCICC 40360 was improved by genome shuffling while simultaneously enhancing the ethanol resistance. The initial mutant population was generated by nitrosoguanidine treatment of the spores, and an improved population producing more than fivefold ethanol than wild type was obtained by genome shuffling. The results show that the shuffled strain HJ48 can efficiently convert lignocellulosic sugars to ethanol under aerobic conditions. Furthermore, it was able to produce ethanol directly from sugarcane bagasse, demonstrating that the shuffled strain HJ48 is a suitable microorganism for consolidated bioprocessing.

scholarly journals Ethanol Production from Nondetoxified Dilute-Acid Lignocellulosic Hydrolysate by Cocultures of Saccharomyces cerevisiae Y5 and Pichia stipitis CBS6054

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Ping Wan ◽  
Dongmei Zhai ◽  
Zhen Wang ◽  
Xiushan Yang ◽  
Shen Tian
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Synthetic Medium ◽  
Pichia Stipitis ◽  
Dilute Acid ◽  
Acid Hydrolysate ◽  
Issatchenkia Orientalis ◽  
Final Ethanol Concentration

Saccharomyces cerevisiae Y5 (CGMCC no. 2660) and Issatchenkia orientalis Y4 (CGMCC no. 2159) were combined individually with Pichia stipitis CBS6054 to establish the cocultures of Y5 + CBS6054 and Y4 + CBS6054. The coculture Y5 + CBS6054 effectively metabolized furfural and HMF and converted xylose and glucose mixture to ethanol with ethanol concentration of 16.6 g/L and ethanol yield of 0.46 g ethanol/g sugar, corresponding to 91.2% of the maximal theoretical value in synthetic medium. Accordingly, the nondetoxified dilute-acid hydrolysate was used to produce ethanol by co-culture Y5 + CBS6054. The co-culture consumed glucose along with furfural and HMF completely in 12 h, and all xylose within 96 h, resulting in a final ethanol concentration of 27.4 g/L and ethanol yield of 0.43 g ethanol/g sugar, corresponding to 85.1% of the maximal theoretical value. The results indicated that the co-culture of Y5 + CBS6054 was a satisfying combination for ethanol production from non-detoxified dilute-acid lignocellulosic hydrolysates. This co-culture showed a promising prospect for industrial application.

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