Co-culture strategy for improved 2G bioethanol production using a mixture of sugarcane molasses and bagasse hydrolysate as substrate

International audienceMixed sugar co-fermentation represents an interesting fermentation strategy to improve bioethanol production from low-cost raw materials, such as sugarcane bagasse. The aim of this study was to evaluate a mixture of sugars (hexoses and pentoses) from sugarcane bagasse hemicellulosic hydrolysate diluted with sugarcane molasses as substrate to be converted either in monoculture or co-culture fermentations. A co-culture fermentation technique using hexoses-fermenting yeasts (Saccharomyces cerevisiae: from Santa Adélia Mill, an industrial strain (SA) and a respiratory-deficient mutant strain (ScP)) together with xylose-fermenting yeasts (Scheffersomyces stipitis (SS) and Spathaspora passalidarum (SP)) was carried out to enhance bioethanol production. Co-culture fermentation in a medium with a high mixed sugar concentration (100 g/L) resulted in a complete sugar consumption, ethanol titer of 30.2 g/L and increased ethanol productivity (Qp =4.44 g/Lh) using wild type strains (SP+SA). In contrast, the maximum ethanol titer (49.2 g/L) was reached during co-cultureperformed with S. stipitis and the respiratory-deficient mutant strain of S. cerevisiae, however ethanol productivity (Qp =0.60 g/Lh) decreased due to the poor fermentation performance of the mutant strain. This work suggests that improved efficiency and good scalability of the mixed sugar fermentation process makes an important basis for the economic viability of bioethanol production from lignocelluloses

Separation Of Fructooligosaccharides Using Zeolite Fixed Bed Columns.

Recent studies have shown that the chromatographic separation of mixtures of monosaccharides and disaccharides may be improved by employing Y zeolites, a procedure which holds promise in the separation of oligosaccharides. In the present study, a column packed with zeolite was employed to study the separation of fructooligosaccharides (FOS). FOS were produced by an enzyme isolated from Rhodotorula sp., which produces GF(2) (kestose), GF(3) (nystose) and GF(4) (frutofuranosyl nystose). The identification and quantification of the sugars were carried out by ion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The separation of fructooligosaccharides was carried out using a fixed bed column packed with Ba(2+)-exchange Y zeolites. The effects of temperature (40-50 degrees C), injected volume per bed volume (2.55-7.64%), superficial velocity (0.1-0.15cmmin(-1)) and eluent composition (40-60% ethanol) were investigated using a fractionary factorial design with separation efficiency as the response. The results showed that the most favorable conditions for the separation of the oligosaccharide-glucose mixture were 60% ethanol as eluent, temperature of 50 degrees C, superficial velocity of 0.1cmmin(-1) and 2.55% injection volume per bed volume of injection mixture, using two columns in series. The values for separation efficiency were 0.60 for oligosaccharide-glucose, 1.00 for oligosaccharide-fructose, 0.22 for oligosaccharide-sucrose, 0.43 for glucose-fructose, 0.82 for glucose-sucrose and 1.23 for fructose-sucrose

Review: bacterias lácticas: funcionalidad, polisacáridos, potencial terapéutico y aplicaciones en alimentos

This review shows the recent acid lactic bacteria advances, their functional and therapeutic potential, synthesis of polisaccharides and their possibilities of application in the cultures of starter industry, foods and healthful-foods. There are included topics that go from the origin of the lactic acid bacteria (LAB), tipic and industrial products applications, their biological and genetic characteristics, description of a diverse number of strains, their main products of fermentation, with a greater approach in the exo-polisaccharides producing for the application in the food industry, as well as concepts and advances in functional food like the symbiotic ones, until the future perspective of researchs.Esta revisión bibliográfica muestra los adelantos recientes en relación con las bacterias lácticas, su potencial funcional y terapéutico, en la síntesis de polisacáridos y sus posibilidades de aplicación en la industria de cultivos starter, alimentos y alimentos-saludables. Se abarcan tópicos, tales como, el origen de las bacterias lácticas (BAL), aplicaciones artesanales e industriales, sus características biológicas y genéticas, descripción de un número diverso de especies, los principales productos de fermentación, con un enfoque mayor en la obtención de ex polisacáridos para aplicación en la industria de alimentos, así como conceptos y avances en alimentos funcionales como los simbióticos, incluyendo las perspectivas futuras de investigación

Alcoholic fermentation from sugarcane molasses and enzymatic hydrolysates: modeling and sensitivity analysis

Ethanol competitivity can be enhanced when the total use of sugarcane portions is practicable, including bagasse and straw, through hydrolysis technology, in which the polysaccharides are processed to produce fermentable sugar and posteriorly ethanol. Among the problems of hydrolysate fermentation is the low sugar concentration in the medium (when hydrolysis is performed at low solids loading), which leads to low ethanol concentration, increasing the energy requirement in distillation. This can be solved through the concentration of hydrolysates with molasses. Kinetics of a mixture hydrolysates - molasses changes significantly from that of molasses, due to presence of other sugars and inhibitors. Thus, the kinetic models developed for molasses are not useful to predict fermentation data for hydrolysates. Considering this, in this work, a kinetic model for fermentation of a mixture of sugarcane bagasse hydrolysate and molasses was developed. For this purpose, data from batch fermentations at temperatures of 30, 32, 34, 36 e 38 degrees C were used. The model for hydrolysates was based on kinetic expressions previously developed for molasses fermentation, with addition of a term considering acetic acid inhibition on Saccharomyces cerevisiae growth. Also, to describe the data for fermentations with hydrolysate, a parameter re-estimation was necessary. Due to the large number of parameters in the model, a re-estimation methodology was proposed, in which the most sensitive parameters were adjusted and the less sensitive were kept fixed, making the re-estimation easier. A parametric sensitivity analysis through Plackett-Burman designs was performed, using the software Statistica, by varying the kinetic parameters and calcullating their influence on the profiles of cell, substrate and ethanol concentrations. The model consisted of 13 parameters, of which 5 were considered as relevant on fermentation profiles (mu(max), P-max. Y-x, Y-p/x and X-max) and chosen to be re-estimated. Through the use of this methodology, an accurate model for second generation bioethanol production was developed37349354sem informaçãoInternational Conference on BioMass (iconBM 2014)sem informaçã

Clavulanic Acid Adsorption Studies in Zeolites

Zeolites are crystalline inorganic solids containing aluminium, silicon and oxygen arranged in a highly regular structure, and they are usually used in separation processes. In this study, zeolites have been shown to act as adsorbents for clavulanic acid. Ion exchange with different compensating cations (Na + , K + , Ca 2+ , Ba 2+ , Mg 2+ , Sr 2+ ) was used to modify the natural zeolite (NZ) and the synthetic faujasite (13X). Kinetic analysis of the adsorption of clavulanic acid indicated that the 13X-Na zeolite was the most appropriate for this purpose. Under equilibrium conditions, the retention by this zeolite was about 17.4% (C*/C 0 = 0.826), with the amount of clavulanic acid adsorbed relative to the amount of zeolite employed (q*) being ca. 0.5 mg/g. The 13X-Na zeolite was characterized in terms of its Si/Al ratio (1.5), density (d z = 2.248 g/cm 3 ), superficial area (S BET = 444.860 m 2 /g), total pore volume (V pore = 0.308 cm 3 /g), micropore volume (V micro = 0.203 cm 3 /g) and particle porosity (ε p = 0.69). Adsorption isotherms at 10, 15 and 20 °C were constructed using 13X-Na zeolite and solutions of pure clavulanic acid; these demonstrated that the lower the temperature, the higher the amount of clavulanic acid adsorbed

Concentration profiles in batch fermentation of hydrolyzed lignocellulose

Experimental data was obtained for profiling changes in concentrations of two inhibiting compounds in batch fermentation of a synthesized liquor resembling hydrolyzed lignocellulose, a furan (furfural) and a phenolic compound (vanillin), along with standard fermentation data, i.e. substrate, biomass and ethanol concentrations. The initial inhibitor concentrations and fermentation temperatures in the 18 experiments were varied according to a two-level complete center composite experimental design. Based upon these observed variations in the fermentative behavior, the fermentation kinetics were modeled, as published in the corresponding article, including microbial conversion rates of the inhibitive compounds into their less toxic derivatives

Acetone-free biobutanol production: past and recent advances in the isopropanol-butanol-ethanol (IBE) fermentation

Production of butanol for fuel via the conventional Acetone-Butanol-Ethanol fermentation has been considered economically risky because of a potential oversupply of acetone. Alternatively, acetone is converted into isopropanol by specific solventogenic Clostridium species in the Isopropanol-Butanol-Ethanol (IBE) fermentation. This route, although less efficient, has been gaining attention because IBE mixtures are a potential fuel. The present work is dedicated to reviewing past and recent advances in microorganisms, feedstock, and fermentation equipment for IBE production. In our analysis we demonstrate the importance of novel engineered IBE-producing Clostridium strains and cell retention systems to decrease the staggering number of fermentation tanks required by IBE plants equipped with conventional technology. We also summarize the recent progress on recovery techniques integrated with fermentation, especially gas stripping. In addition, we assessed ongoing pilotplant efforts that have been enabling IBE production from woody feedstock287FAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paulo2015/20630-4, 2016/23042-9, 2018/23983-

Optimization of inulinase production by kluyveromyces marxianus using factorial design

Factorial design and response surface techniques were used to optimize the culture medium for the production of inulinase by Kluyveromyces marxianus. Sucrose was used as the carbon source instead of inulin. Initially, a fractional factorial design (25–1) was used in order to determine the most relevant variables for enzyme production. Five parameters were studied (sucrose, peptone, yeast extract, pH, and K2HPO4), and all were shown to be significant. Sucrose concentration and pH had negative effects on inulinase production, whereas peptone, yeast extract, and K2HPO4 had positive ones. The pH was shown to be the most significant variable and should be preferentially maintained at 3.5. According to the results from the first factorial design, sucrose, peptone, and yeast extract concentrations were selected to be utilized in a full factorial design. The optimum conditions for a higher enzymatic activity were then determined: 14 g/L of sucrose, 10 g/L of yeast extract, 20 g/L of peptone, 1 g/L of K2HPO4. The enzymatic activity in the culture conditions was 127 U/mL, about six times higher than before the optimization

Modelling, simulation and factorial design as tools for the in silico process optimisation of fructooligosaccharide production by immobilised fructosyltransferase in a basket reactor

Modelling, simulation and optimisation of the production of fructooligosaccharides (FOS) by fructosyltransferase immobilised on inorganic niobium support and applied in a basket reactor (BR) were used for in silico optimisation of the process. Simulink and MATLAB 6.0 were used as computational tools. The kinetic process data were obtained experimentally using purified fructosyltransferase produced by Rhodotula sp. Optimisation experiments were carried out using simulation, according to the factorial design methodology, using a two central composite rotatable design. In the first design, the variables with the highest influence were determined; in the second design, the conditions to produce FOS were optimised. The optimum conditions were 14 Ui/ml for the activity of enzyme, immobilised in a niobium ore, and a stirring speed of 45 rpm. Under these conditions, FOS yield was 50.6% after 24 h of synthesis, at 50°C and pH 4.5. The results demonstrated the good efficiency of the BR, as well as showing that the film mass transfer coefficient around the biocatalyst has a significant influence during the reaction and production of FOS3218492FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informaçã