Effects of the carbon source and the interaction between carbon sources on the physiology of the industrial Saccharomyces cerevisiae CAT-1.

During industrial fermentation, wild isolates are able to persist and even predominate in the bioreactors. Saccharomyces cerevisiae CAT-1 was one of these isolates and now is one of the yeasts mostly used in industrial ethanol processes in Brazil due to its efficient fermentation capacity. Despite it, the strain's physiology has been marginally studied so far. Since strains of the same species may have different responses to a specific cultivation condition, this work aimed to evaluate the physiology of S. cerevisiae CAT-1 in batch cultures using different carbon sources (glucose, fructose, sucrose, maltose, and galactose) as a sole carbon source and in binary mixtures, at 30 and 37 °C. The results showed that the fructose, sucrose, and maltose were the sugars that presented the highest ethanol yields on the substrate (0.40 gethanol gsubstrate-1) at both temperatures. Galactose was the sugar that the yeast had the lowest affinity given the lowest maximum specific growth rate (0.28 h-1). Despite the influence of a variety of mechanisms for sugar transport, the cells consume first substrates with fewer metabolic steps to catabolism and are susceptible to adaptive evolution depending on the availability of substrate.

Evaluation of the Fermentative Capacity of Saccharomyces cerevisiae CAT-1 and BB9 Strains and Pichia kudriavzevii BB2 at Simulated Industrial Conditions.

The search for promising yeasts that surpass the fermentative capacity of commercial strains, such as Saccharomyces cerevisiae CAT-1, is of great importance for industrial ethanol processes in the world. Two yeasts, Pichia kudriavzevii BB2 and Saccharomyces cerevisiae BB9, were evaluated in comparison to the industrial yeast S. cerevisiae CAT-1. The objective was to evaluate the performance profile of the three studied strains in terms of growth, substrate consumption, and metabolite formation, aiming to determine their behaviour in different media and pH conditions. The results showed that under cultivation conditions simulating the medium used in the industrial process (must at 22° Brix at pH 3.0) the highest ethanol productivity was 0.41 g L-1 h-1 for S. cerevisiae CAT-1, compared to 0.11 g L-1 h-1 and 0.16 g L-1 h-1 for P. kudriavzevii and S. cerevisiae BB2, respectively. S. cerevisiae CAT-1 produced three times more ethanol in must at pH 3.0 (28.30 g L-1) and in mineral medium at pH 3.0 (29.17 g L-1) and 5.0 (30.70 g L-1) when compared to the value obtained in sugarcane must pH 3.0 (9.89 g L-1). It was concluded that S. cerevisiae CAT-1 was not limited by the variation in pH in the mineral medium due to its nutritional composition, guaranteeing better performance of the yeast even in the presence of stressors. Only S. cerevisiae CAT-1 expressed he constitutive invertase enzyme, which is responsible for hydrolysing the sucrose contained in the must.

Control of pathogens in fresh pork sausage by inclusion of Lactobacillus sakei BAS0117.

A pork sausage was produced with low sodium content (1.64%) to which Lactobacillus sakei was added with the aim of developing a meat pork sausage for cooking and having technological, organoleptic, and hygienic advantages. The lactic acid bacteria (LAB) L. sakei, Lactococcus sp., and Pediococcus pentosaceus were submitted to extreme pH, temperature, and NaCl conditions. Lactobacillus sakei was used in pork sausage because of its resistance to different culture conditions and its antimicrobial potential. The food-borne pathogens Listeria monocytogenes Scott A, Enterococcus faecalis, and Staphylococcus aureus were used as indicator microorganisms to evaluate the antimicrobial activity of selected LAB strains. Salmonella enterica serotype Choleraesuis is a common pathogen of pigs. To the raw sausage product containing L. sakei and nonpathogenic endogenous microbiota, we added about >104 and <105 CFU/g of S. enterica serotype Choleraesuis to evaluate the inhibitory potential of L. sakei towards this pathogen. Salmonella Choleraesuis was inhibited in the presence of L. sakei over 7 days of storage of the meat product (about 3.0 log cycles reduction). Lactobacillus sakei significantly increased inhibition when compared with the nonfermented sausage. Thus, L. sakei BAS0117 played an important role as an additional hurdle in the fermented meat pork sausage during storage.

Catalytic and thermodynamic properties of ß-glucosidases produced by Lichtheimia corymbifera and Byssochlamys spectabilis.

The objective of the present study was to optimize parameters for the cultivation of Lichtheimia corymbifera (mesophilic) and Byssochlamys spectabilis (thermophilic) for the production of ß-glucosidases and to compare the catalytic and thermodynamic properties of the partially purified enzymes. The maximum amount of ß-glucosidase produced by L. corymbifera was 39 U/g dry substrate (or 3.9 U/mL), and that by B. spectabilis was 77 U/g (or 7.7 U/mL). The optimum pH and temperature were 4.5 and 55 °C and 4.0 and 50 °C for the enzyme from L. corymbifera and B. spectabilis, respectively. ß-Glucosidase produced by L. corymbifera was stable at pH 4.0-7.5, whereas the enzyme from B. spectabilis was stable at pH 4.0-6.0. Regarding the thermostability, ß-glucosidase produced by B. spectabilis remained stable for 1 h at 50 °C, and that from L. corymbifera was active for 1 h at 45 °C. Determination of thermodynamic parameters confirmed the greater thermostability of the enzyme produced by the thermophilic fungus B. spectabilis, which showed higher values of ΔH, activation energy for denaturation (Ea), and half-life t(1/2). The enzymes were stable in the presence of ethanol and were competitively inhibited by glucose. These characteristics contribute to their use in the simultaneous saccharification and fermentation of vegetable biomass.

Biochemical characterization and evaluation of invertases produced from Saccharomyces cerevisiae CAT-1 and Rhodotorula mucilaginosa for the production of fructooligosaccharides.

Invertases are used for several purposes; one among these is the production of fructooligosaccharides. The aim of this study was to biochemically characterize invertase from industrial Saccharomyces cerevisiae CAT-1 and Rhodotorula mucilaginosa isolated from Cerrado soil. The optimum pH and temperature were 4.0 and 70 °C for Rhodotorula mucilaginosa invertase and 4.5 and 50 °C for Saccharomyces cerevisiae invertase. The pH and thermal stability from 3.0 to 10.5 and 75 °C for R. mucilaginosa invertase, respectively. The pH and thermal stability for S. cerevisiae CAT-1 invertase from 3.0 to 7.0, and 50 °C, respectively. Both enzymes showed good catalytic activity with 10% of ethanol in reaction mixture. The hydrolysis by invertases occurs predominantly when sucrose concentrations are ≤5%. On the other hand, the increase in the concentration of sucrose to levels above 10% results in the highest transferase activity, reaching about 13.3 g/L of nystose by S. cerevisiae invertase and 12.6 g/L by R. mucilaginosa invertase. The results demonstrate the high structural stability of the enzyme produced by R. mucilaginosa, which is an extremely interesting feature that would enable the application of this enzyme in industrial processes.

Production and Catalytic Properties of Amylases from Lichtheimia ramosa and Thermoascus aurantiacus by Solid-State Fermentation.

The present study compared the production and the catalytic properties of amylolytic enzymes obtained from the fungi Lichtheimia ramosa (mesophilic) and Thermoascus aurantiacus (thermophilic). The highest amylase production in both fungi was observed in wheat bran supplemented with nutrient solution (pH 4.0) after 96 hours of cultivation, reaching 417.2 U/g of dry substrate (or 41.72 U/mL) and 144.5 U/g of dry substrate (or 14.45 U/mL) for L. ramosa and T. aurantiacus, respectively. The enzymes showed higher catalytic activity at pH 6.0 at 60°C. The amylases produced by L. ramosa and T. aurantiacus were stable between pH 3.5-10.5 and pH 4.5-9.5, respectively. The amylase of L. ramosa was stable at 55°C after 1 hour of incubation, whereas that of T. aurantiacus maintained 60% of its original activity under the same conditions. Both enzymes were active in the presence of ethanol. The enzymes hydrolyzed starch from different sources, with the best results obtained with corn starch. The enzymatic complex produced by L. ramosa showed dextrinizing and saccharifying potential. The enzymatic extract produced by the fungus T. aurantiacus presented only saccharifying potential, releasing glucose monomers as the main hydrolysis product.

Optimization of parameters for obtaining surimi-like material from mechanically separated chicken meat using response surface methodology.

Surimi is a semi-processed washed fish mince protein concentrate mixed with cryoprotectants for frozen storage, which is the primary constituent of processed foods. Mechanically separated chicken meat (MSCM) is a common ingredient of comminuted sausages mainly due to its low price. The present work aimed to define the adequate parameters to obtain surimi-like material from MSCM using response surface methodology, and to characterize the chemical and textural properties of this product. The MSCM was utilized in the elaboration of surimi-like material using the bleaching method with sodium bicarbonate and sodium chloride solutions. For this purpose, the effect of process parameters viz: temperature (T = 2, 7, and 12 °C), time (t = 5, 10, and 15 min/cycles) and washing solution:MSCM ratio (R = 2:1, 4:1, and 6:1 w/w) were evaluated using response surface methodology. The highest composite design averages obtained were 10.7 % for protein content, 1,003.4 g for breaking force, 645.8 g.cm for gel strength, 9.0 N for cutting strength, and 24.1 N.s for work of shearing at the optimum combination of processing conditions of 7 °C, 10 min and 4:1 washing solution:MSCM ratio, corresponding to the central points of the proposed experimental design. The obtained models had high determination coefficients, explaining 95.85, 98.23, 98.41, and 96.08 % of total variability in protein content, cutting strength, breaking force, and work of shearing variabilities, respectively. According to the folding test the surimi-like material presented the same characteristics of a high quality surimi (FT = 5).

Physiology of Lichtheimia ramosa obtained by solid-state bioprocess using fruit wastes as substrate.

Due to the amount of nutrients available in the agroindustrial wastes, these can be converted into high added-value products by the action of microorganisms in solid-state bioprocesses. The aim of this work was to evaluate the growth physiology and lipase production of the fungus Lichtheimia ramosa using the following Brazilian savannah fruit wastes as substrates: bocaiuva (Acrocomia aculeata), pequi (Caryocar brasiliense), guavira (Campomanesia pubescens), araticum (Annona crassiflora) and seriguela (Spondias purpurea). These residues were triturated, homogenized, adjusted to pH 5.0 and 60 % moisture, sterilized and packaged in plastic tray-type bioreactors before inoculation with 10 % (w/v) of L. ramosa pre-culture medium. The cultivations were conducted in a bacteriological incubator at 30 °C for 40 days. Samples were taken every 5 days and fungi and bacteria contents, proximate composition and lipase activity were evaluated. The maximum fungal counting was observed between 25 and 35 days. L. ramosa reached the stationary phase next to 40 days in all substrates. Mesophilic and psicrophilic aerobic bacteria were not detected. Protein enrichment was obtained for all media, being superior in seriguela residues (391.66 %), followed by pequi (160.04 %), araticum (143.31 %), guavira (102.42 %), and bocaiuva (67.88 %). Lipase production was observed in all cultivated media, except in pequi residues that showed decreasing lipase activity. The higher production was observed in guavira (1.12 U/g) followed by araticum (0.58 U/g), seriguela (0.41 U/g) and bocaiuva (0.21 U/g) waste substrates. It was concluded that the studied fruit wastes have been successfully utilized as substrates for protein enrichment and lipase production with L. ramosa.

Characterization of wami tilapia (Oreochromis urolepis hornorum) skin gelatin: microbiological, rheological and structural properties.

Gelatin was extracted from the skin of tilapia (Oreochromis urolepis hornorum) and its microbiological, rheological and structural properties were characterized. The tilapia skin gelatin presented typical molecular weight distribution of type I collagen with contents of imino acids (proline + hydroxyproline) of 21.67%. Gel strength and viscosity values were 221 ± 5.68 g and 5.98 ± 0.34 cP, respectively, with the maturation time of 18 ± 1 h, and both parameters increased with the maturation time. Melting and gelling points of 25 degrees C and 21 degrees C, respectively, were obtained for tilapia skin gelatin. The gelatin presented microbiological standards in accordance with the Brazilian Legislation.

Physiological evaluation of yeast strains under anaerobic conditions using glucose, fructose, or sucrose as the carbon source.

The aim of this study was to evaluate the physiology of 13 yeast strains by assessing their kinetic parameters under anaerobic conditions. They included Saccharomyces cerevisiae CAT-1 and 12 isolated yeasts from different regions in Brazil. The study aimed to enhance understanding of the metabolism of these strains for more effective applications. Measurements included quantification of sugars, ethanol, glycerol, and organic acids. Various kinetic parameters were analyzed, such as specific substrate utilization rate (qS), maximum specific growth rate (µmax), doubling time, biomass yield, product yield, maximum cell concentration, ethanol productivity (PEth), biomass productivity, and CO2 concentration. S. cerevisiae CAT-1 exhibited the highest values in glucose for µmax (0.35 h-1), qS (3.06 h-1), and PEth (0.69 gEth L-1 h-1). Candida parapsilosis Recol 37 did not fully consume the substrate. In fructose, S. cerevisiae CAT-1 stood out with higher values for µmax (0.25 h-1), qS (2.24 h-1), and PEth (0.60 gEth L-1 h-1). Meyerozyma guilliermondii Recol 09 and C. parapsilosis Recol 37 had prolonged fermentation times and residual substrate. In sucrose, only S. cerevisiae CAT-1, S. cerevisiae BB9, and Pichia kudriavzevii Recol 39 consumed all the substrate, displaying higher PEth (0.72, 0.51, and 0.44 gEth L-1 h-1, respectively) compared to other carbon sources.

Growth of the yeast Kluyveromyces marxianus CBS 6556 on different sugar combinations as sole carbon and energy source.

The yeast Kluyveromyces marxianus has been pointed out as a promising microorganism for a variety of industrial bioprocesses. Although genetic tools have been developed for this yeast and different potential applications have been investigated, quantitative physiological studies have rarely been reported. Here, we report and discuss the growth, substrate consumption, metabolite formation, and respiratory parameters of K. marxianus CBS 6556 during aerobic batch bioreactor cultivations, using a defined medium with different sugars as sole carbon and energy source, at 30 and 37 °C. Cultivations were carried out both on single sugars and on binary sugar mixtures. Carbon balances closed within 95 to 101 % in all experiments. Biomass and CO2 were the main products of cell metabolism, whereas by-products were always present in very low proportion (<3 % of the carbon consumed), as long as full aerobiosis was guaranteed. On all sugars tested as sole carbon and energy source (glucose, fructose, sucrose, lactose, and galactose), the maximum specific growth rate remained between 0.39 and 0.49 h(-1), except for galactose at 37 °C, which only supported growth at 0.31 h(-1). Different growth behaviors were observed on the binary sugar mixtures investigated (glucose and lactose, glucose and galactose, lactose and galactose, glucose and fructose, galactose and fructose, fructose and lactose), and the observations were in agreement with previously published data on the sugar transport systems in K. marxianus. We conclude that K. marxianus CBS 6556 does not present any special nutritional requirements; grows well in the range of 30 to 37 °C on different sugars; is capable of growing on sugar mixtures in a shorter period of time than Saccharomyces cerevisiae, which is interesting from an industrial point of view; and deviates tiny amounts of carbon towards metabolite formation, as long as full aerobiosis is maintained.

Effects of soybean protein, potato starch and pig lard on the properties of frankfurters formulated from mechanically separated chicken meat surimi-like material.

Mechanically separated chicken meat has become a common ingredient of comminuted sausage products, as 'frankfurters', mainly due to its low price. The present work aimed to develop a frankfurter from mechanically separated chicken meat surimi-like material, and evaluated the chemical, rheological, microbiological and sensorial properties of this product. The response surface methodology was utilized to investigate the effects of the soybean protein, potato starch and pig lard on the texture of the obtained frankfurters. For this purpose, five levels of each factor were evaluated: soybean protein varied from 0% to 6%, potato starch from 0% to 10% and pig lard from 2% to 12%. The regression analysis of the model showed that the soybean protein exerted a linear positive effect and a quadratic negative effect in the compression force of the product (p < 0.05), and that the variable which more influenced the shear force was the potato starch, presenting linear and quadratic effects (p < 0.05). The highest composite design averages obtained were 202.2 g for breaking force, 7.9 cm for deformation, 10.1 N for shear force, and 90.9 N.s for work of shearing. The obtained models presented high determination coefficients, explaining 97.31%, 97.83%, 97.49%, and 95.39% of the breaking force, deformation, shear force and work of shearing variabilities, respectively. The microbiological analysis demonstrated that the achieved results were below the limits fixed by the FDA. The mechanically separated chicken meat surimi-like material frankfurter presented 72.2% of acceptability and 59.3% of the examiners found the color of the product slightly lighter than the ideal. Finally, the frankfurter-type sausages, without pork fat, produced and characterized here have presented promising characteristics for commercial applications.

Metabolic engineering of Kluyveromyces marxianus for biomass-based applications.

Kluyveromyces marxianus ATCC 26,548 was cultivated in aerobic chemostats with [1-13C] and [U-13C] glucose as carbon source under three different growth conditions (0.10, 0.25, and 0.5 h-1) to evaluate metabolic fluxes. Carbon balances closed always within 97-102%. Growth was carbon limited, and the cell yield on glucose was the same. The extracellular side-product formation was very low, totaling 0.0008 C-mol C-mol-1 substrate at 0.5 h-1. The intracellular flux ratios did not show significant variation for metabolic flux analysis from labelling and biomass composition and metabolic flux ratio analysis from labelling. The observed strictly oxidative metabolism and the stability of the metabolism in terms of fluxes even at high growth rates, without triggering out the synthesis of by-products, is an extremely desired condition that underlines the potential of K. marxianus for biotechnological biomass-related applications and the comprehension of the metabolic pools and pathways is an important step to engineering this organism. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-022-03324-x.

Remediation Capacity of Different Microalgae in Effluents Derived from the Cigarette Butt Cleaning Process.

Microalgal-based remediation is an ecofriendly and cost-effective system for wastewater treatment. This study evaluated the capacity of microalgae in the remediation of wastewater from cleaning process of smoked cigarette butts (CB). At laboratory scale, six strains (one from the family Scenedesmaceae, two Chlamydomonas debaryana and three Chlorella sorokiniana) were exposed to different CB wastewater dilutions to identify toxicity levels reflected in the alteration of microalgal physiological status and to determine the optimal conditions for an effective removal of contaminants. CB wastewater could impact on microalgal chlorophyll and carotenoid production in a concentration-dependent manner. Moreover, the resistance and remediation capacity did not only depend on the microalgal strain, but also on the chemical characteristics of the organic pollutants. In detail, nicotine was the most resistant pollutant to removal by the microalgae tested and its low removal correlated with the inhibition of photosynthetic pigments affecting microalgal growth. Concerning the optimal conditions for an effective bioremediation, this study demonstrated that the Chlamydomonas strain named F2 showed the best removal capacity to organic pollutants at 5% CB wastewater (corresponding to 25 butts L−1 or 5 g CB L−1) maintaining its growth and photosynthetic pigments at control levels.

UV-B Irradiation Effect on Microalgae Performance in the Remediation of Effluent Derived from the Cigarette Butt Cleaning Process.

In this study, the potential of ultraviolet B (UV-B) radiation to alleviate the effects of pollutants in cigarette butt wastewater (CBW) was investigated using different Chlorella sorokiniana strains (F4, R1 and LG1). Microalgae were treated with UV-B (1.7 W m-2) for 3 days prior to their exposure to CBW and then incubated for 4 days in the absence or presence of UV-B. UV-B-untreated microalgae were used as the control. Comparative physiological responses, including photosynthetic pigments and non-enzymatic antioxidants, as well as nicotine and nicotyrine removal, were evaluated in 7-day cultures. UV-B treatments did not negatively impact algal chlorophyll or carotenoid production. UV-B acclimation was strain-dependent, correlating with native environment adaptations and genetic constitutions. UV-B as a pretreatment had long-term positive effects on non-enzymatic antioxidant capacity. However, LG1 needed more time to readjust the pro-oxidant/antioxidant balance, as it was the most UV-B-sensitive. Phenolic compounds played an important role in the antioxidant system response to UV-B, while flavonoids did not contribute to the total antioxidant capacity. Although cross-resistance between UV-B and CBW was observed in F4 and R1, only R1 showed nicotine/nicotyrine catabolism induction due to UV-B. Overall, the results suggest that UV-B activates defense pathways associated with resistance or tolerance to nicotine and nicotyrine.

Influence of luminosity, carbon source and concentration of salts in the physiology of Chlorella sorokiniana.

Growth studies are important to increase the knowledge about the physiology of microalgae. The development of suitable culture media allows optimum growth to each species. The genus Chlorella has the ability to adapt to various environmental and nutritional conditions. Thus, the aim of this work was to evaluate the physiology of Chlorella sorokiniana CTT 7727 at different growth conditions with Basal Bold (BB) medium. For that, heterotrophic, autotrophic and mixotrophic cultures were carried out. The maximum specific growth rates (µmax), the maximum biomass concentrations (Xmax) and cell productivities (PX) were calculated for each experiment. Among all the treatments evaluated, that with 24 h light, 3x BB (g L-1) and CO2 presented a higher µmax (0.40 day-1) and maximum cell concentration due the increased concentration of nutrients. Replacement of dark to light has increased Xmax from 2.3 × 105 to 9.3 × 106 cells mL-1 in regular BB medium and 3.6 × 105 to 2.1 × 107 cells mL-1 in 3x BB medium in autotrophic cultivations. The PX increased from 2.4 × 104 cells mL-1 h-1 (1x BB (g L-1)) to 3.6 × 104 cells mL-1 h-1 (3x BB (g L-1)), in the presence of 24 light and CO2. However, the same behaviour was not observed when BB concentration was increased 6, 8 or 10 times the initial concentration of BB medium. Experiments with pulses of concentrated nutrients showed that declining cells can resume their growth after nutrient depletion, but the viability is decreased after successive pulses.

Effects of the carbon source on the physiology and invertase activity of the yeast Saccharomyces cerevisiae FT858.

Saccharomyces cerevisiae FT858 is an industrial yeast strain with high fermentative efficiency, but marginally studied so far. The aim of this work was to evaluate the biotechnological potential of S. cerevisiae FT858 through kinetic growth parameters, and the influence of the concentration of the substrate on the synthesis of the invertase enzyme. Invertases have a high biotechnological potential and their production through yeast is strongly influenced by the sugars in the medium. S. cerevisiae FT858 has an excellent biotechnological potential compared to the industrial yeast reference S. cerevisiae CAT-1, as it presented a low glycerol yield on the substrate (Y GLY/S) and a 10% increase in ethanol yield on sucrose in cultures with sucrose at 37 °C. The substrate concentration directly interfered in invertase production and the enzymatic expression underwent strong regulation through glucose concentration in the culture medium and S. cerevisiae CAT-1 presented constitutive behavior for the invertase enzyme.

Development and characterization of biopolymer films based on bocaiuva (Acromonia aculeata) flour.

This work aimed to produce films based on bocaiuva flour (Acrocomia aculeata) by the casting method, and to characterise them. All obtained films were visually symmetrical, without ruptures or blistering and visually homogeneous, easy to handle with a yellowish colouration. The addition of glycerol allowed greater flexibility to the films. The tensile strength and the elongation increase as the concentration of flour increased (2.04 g 100 mL-1). The addition of oily phases increases the elongation, indicating that the essential oil incorporated into the films acted as plasticizer because it also allowed a greater permeability to water vapor. Peaks at 2Ɵ between 10.00°, 13.81°, 17.67°, 20.0° and 24.34° were observed in films with 12.56 g of starch per 100 g of pulp, which are characteristic of B-starch, due to the presence of long branched chains of amylopectin, with a peak characteristic of lignocellulosic materials. Reflection was more intense at 2Ɵ between 22° for all treatments. The obtained films presented relevant characteristics for the application as edible coating.

Physiology of yeast strains isolated from Brazilian biomes in a minimal medium using fructose as the sole carbon source reveals potential biotechnological applications.

The aim of this study was to evaluate the kinetic parameters and the production of metabolites of 13 novel yeasts isolated from a distillery and fruits, and Saccharomyces cerevisiae CAT-1, cultivated in fructose-based medium. The yeasts with the highest µ max were obtained from must, Pichia kudriavzevii BB2, P. kudriavzevii BB1, and S. cerevisiae BB9 (0.47-0.49 h-1). S. cerevisiae CAT-1 (3.02 g gDCM-1 h-1), S. cerevisiae BB9 (3.01 g gDCM-1 h-1), and Candida glabrata Recol 41 (2.52 g gDCM-1 h-1) stood out in terms of µ S. C. parapsilosis Recol 29, and Rhodotorula mucilaginosa Recol 03 strains showed the highest Y X/S (0.30 and 0.28 gDCM g-1, respectively). C. glabrata Recol 10 and S. cerevisiae BB9 strains stood out for their higher substrate conversion rates into ethanol (0.44 and 0.41 gEth gS-1, respectively). R. mucilaginosa Recol 03 presented the poorest performance in substrate consumption (0.87 g gDCM-1 h-1), while the strains isolated from must and C. glabrata Recol 10 showed the highest ethanol production and the C. parapsilosis Recol 29 showed the highest biomass conversion.

Production, characterization, and evaluation of the stability of biodiesel obtained from greasy agroindustrial waste during storage.

Greasy agroindustrial waste from the process of cooking hog meat was used to produce biodiesel (fatty acid methyl esters and fatty acid ethyl esters) under a specific storage condition. The operating conditions necessary to achieve the optimal relationship between quality and productivity were assessed. Next, batches of methyl and ethyl biodiesels were produced, generating 2 L of each product to evaluate their stability during 150 days of storage. The following study indicates that, for methyl route, the molar ratio (1:5) and catalyst (0.5%) yielded the best result of 90.77% (w/v) and quality parameters within the international standards. The ethyl route also showed the highest yield (77.09% w/v) and better quality parameters with a molar ratio (1:5) and catalyst (0.5%). No significant differences were observed in the methyl biodiesel obtained from the batch process for up to 45 days, while the ethyl biodiesel degraded in 30 days of storage.