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1.
A Comparative Study of Various Pretreatment Approaches for Bio-Ethanol Production from Willow Sawdust, Using Co-Cultures and Mono-Cultures of Different Yeast Strains.
Ben Atitallah, I, Antonopoulou, G, Ntaikou, I, Soto Beobide, A, Dracopoulos, V, Mechichi, T, Lyberatos, G
Molecules (Basel, Switzerland). 2022;(4)
Abstract
The effect of different pretreatment approaches based on alkali (NaOH)/hydrogen peroxide (H2O2) on willow sawdust (WS) biomass, in terms of delignification efficiency, structural changes of lignocellulose and subsequent fermentation toward ethanol, was investigated. Bioethanol production was carried out using the conventional yeast Saccharomyces cerevisiae, as well as three non-conventional yeasts strains, i.e., Pichia stipitis, Pachysolen tannophilus, Wickerhamomyces anomalus X19, separately and in co-cultures. The experimental results showed that a two-stage pretreatment approach (NaOH (0.5% w/v) for 24 h and H2O2 (0.5% v/v) for 24 h) led to higher delignification (38.3 ± 0.1%) and saccharification efficiency (31.7 ± 0.3%) and higher ethanol concentration and yield. Monocultures of S. cerevisiae or W. anomalus X19 and co-cultures with P. stipitis exhibited ethanol yields in the range of 11.67 ± 0.21 to 13.81 ± 0.20 g/100 g total solids (TS). When WS was subjected to H2O2 (0.5% v/v) alone for 24 h, the lowest ethanol yields were observed for all yeast strains, due to the minor impact of this treatment on the main chemical and structural WS characteristics. In order to decide which is the best pretreatment approach, a detailed techno-economical assessment is needed, which will take into account the ethanol yields and the minimum processing cost.
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2.
Effects of Mixing Energy Drinks With Alcohol on Driving-Related Skills.
Pérez-Mañá, C, Mateus, JA, Díaz-Pellicer, P, Díaz-Baggerman, A, Pérez, M, Pujadas, M, Fonseca, F, Papaseit, E, Pujol, J, Langohr, K, et al
The international journal of neuropsychopharmacology. 2022;(1):13-25
Abstract
BACKGROUND Energy drinks (EDs) reduce sleepiness and fatigue and improve driving performance whereas alcohol does just the opposite. Although it is a trendy combination among young people, the effects of alcohol mixed with EDs on driving performance have been poorly studied. The aim was to assess if there is an interaction between the effects of both drinks on driving-related skills as well as perceptions about driving ability. METHODS We conducted a randomized, double-blind, and placebo-controlled 4-way crossover clinical trial. Participants were 16 healthy volunteers. Interventions of 60 g of ethanol and 750 mL of Red Bull (RB) were administered in 2 separated doses. Conditions were alcohol + RB placebo, alcohol + RB, alcohol placebo + RB, and both placebos. Objective performance was assessed using a tracking test and simple reaction time, N-Back, and movement estimation tasks. Additionally, willingness to drive, other subjective effects, and ethanol and caffeine blood concentrations were also measured. RESULTS Alcohol increased the time outside the road in the tracking test and increased simple reaction time, but the addition of RB had no main or interaction effects on performance. Nonetheless, driving-related skills after alcohol + RB were better than after alcohol alone. Willingness to drive increased with the combination of drinks. RB also reduced alcohol-induced sedation whereas drunkenness did not change. These effects were seen even though alcohol + RB increased alcohol (14.8%) and caffeine plasma concentrations (17.6%). CONCLUSIONS Mixing EDs with alcohol predisposes consumers to drive under alcohol influence, perhaps in part because EDs counteract its detrimental effects on driving-related skills. Clinicaltrials.gov: NCT02771587.
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3.
Improvement of ethanol production in fed-batch fermentation using a mixture of sugarcane juice and molasse under very high-gravity conditions.
Cruz, ML, de Resende, MM, Ribeiro, EJ
Bioprocess and biosystems engineering. 2021;(3):617-625
Abstract
Ethanol fermentation in very high gravity (VHG) saves energy consumption for ethanol distillation. As the technology offers high ethanol yield and low waste generation and it can be operated at low cost, it could be more efficient at an industrial scale than other ethanol production methods. This work studied ethanol production using a fed-batch bioreactor with a working volume of 1.5 L. The main objective of this research was evaluate the effects of temperature, sugar concentration, and cellular concentration using a Central Composite Design (CCD). Experimental conditions were selected using the surface response technique obtained from the CCD, and the results were validated to test the reproducibility. The following operating conditions were selected: temperature of 27.0 °C, sugar concentration 300.0 g/L, and cell concentration 15.0% (v/v). Under these conditions, after 30 h of fermentation the ethanol concentration, productivity and yield were 135.0 g/L, 4.42 g/(L·h) and 90.0%, respectively. All sugar was completely consumed.
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4.
Hybrid neural network modeling and particle swarm optimization for improved ethanol production from cashew apple juice.
da Silva Pereira, A, Pinheiro, ÁDT, Rocha, MVP, Gonçalves, LRB, Cartaxo, SJM
Bioprocess and biosystems engineering. 2021;(2):329-342
Abstract
A hybrid neural model (HNM) and particle swarm optimization (PSO) was used to optimize ethanol production by a flocculating yeast, grown on cashew apple juice. HNM was obtained by combining artificial neural network (ANN), which predicted reaction specific rates, to mass balance equations for substrate (S), product and biomass (X) concentration, being an alternative method for predicting the behavior of complex systems. ANNs training was conducted using an experimental set of data of X and S, temperature and stirring speed. The HNM was statistically validated against a new dataset, being capable of representing the system behavior. The model was optimized based on a multiobjective function relating efficiency and productivity by applying the PSO. Optimal estimated conditions were: S0 = 127 g L-1, X0 = 5.8 g L-1, 35 °C and 111 rpm. In this condition, an efficiency of 91.5% with a productivity of 8.0 g L-1 h-1 was obtained at approximately 7 h of fermentation.
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5.
Algae: Biomass to Biofuel.
Soni, VK, Krishnapriya, R, Sharma, RK
Methods in molecular biology (Clifton, N.J.). 2021;:31-51
Abstract
Worldwide demand for ethanol alternative fuel has been emerging day by day owing to the rapid population growth and industrialization. Culturing microalgae as an alternative feedstock is anticipated to be a potentially significant approach for sustainable bioethanol biofuel production. Microalgae are abundant in nature, which grow at faster rates with a capability of storing high lipid and starch/cellulose contents inside their cells. This process offers several environmental advantages, including the effective utilization of land, good CO2 sequestration without entering into "food against fuel" dispute. This chapter focuses on the methods and processes used for the production of bioethanol biofuels from algae. Thus, it also covers significant achievements in the research and developments on algae bioethanol production, mainly including pretreatment, hydrolysis, and fermentation of algae biomass. The processes of producing biodiesel, biogas, and hydrogen have also been discussed.
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6.
Thermal adaptation of acetic acid bacteria for practical high-temperature vinegar fermentation.
Matsumoto, N, Osumi, N, Matsutani, M, Phathanathavorn, T, Kataoka, N, Theeragool, G, Yakushi, T, Shiraishi, Y, Matsushita, K
Bioscience, biotechnology, and biochemistry. 2021;(5):1243-1251
Abstract
Thermotolerant microorganisms are useful for high-temperature fermentation. Several thermally adapted strains were previously obtained from Acetobacter pasteurianus in a nutrient-rich culture medium, while these adapted strains could not grow well at high temperature in the nutrient-poor practical culture medium, "rice moromi." In this study, A. pasteurianus K-1034 originally capable of performing acetic acid fermentation in rice moromi was thermally adapted by experimental evolution using a "pseudo" rice moromi culture. The adapted strains thus obtained were confirmed to grow well in such the nutrient-poor media in flask or jar-fermentor culture up to 40 or 39 °C; the mutation sites of the strains were also determined. The high-temperature fermentation ability was also shown to be comparable with a low-nutrient adapted strain previously obtained. Using the practical fermentation system, "Acetofermenter," acetic acid production was compared in the moromi culture; the results showed that the adapted strains efficiently perform practical vinegar production under high-temperature conditions.
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7.
Effects of Acute Alcohol Consumption on Food Intake and Pictorial Stroop Response to High-Calorie Food Cues.
Adams, S, Wijk, E
Alcohol and alcoholism (Oxford, Oxfordshire). 2021;(3):275-283
Abstract
AIMS: We examined (a) the effect of an acute dose of alcohol on the consumption of energy-dense food and (b) on cognitive bias towards high-energy-dense food cues and (3) whether the effect of an acute dose of alcohol on the consumption of energy-dense food would be mediated by cognitive bias towards high-energy-dense food cues. METHODS Heavy social drinkers (n = 40) abstained from drinking for 12 hours before testing. On the test day, participants completed pre-challenge measures of alcohol and food craving, and cognitive bias towards alcohol in a placebo-controlled, double-blind design. Participants performed post-challenge measures of alcohol and food craving, ad lib energy-dense food consumption and cognitive bias. RESULTS We did not observe any of the hypothesized interactions between challenge condition, consumption of energy-dense food and cognitive bias towards high-energy-dense food cues. CONCLUSIONS Our data suggest that acute alcohol consumption does not influence the consumption of energy-dense food or cognitive bias towards high-energy-dense food cues. These findings may reflect that alcohol does not increase the appetitive value of food and food-related cues or that the measures used in this study were not sensitive to detect an effect. Further research is required to determine whether alcohol at higher doses and/or food cues that are frequently paired with alcohol intake stimulates changes in food intake and the reward value of food cues.
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8.
Alcohol-Induced Lysosomal Damage and Suppression of Lysosome Biogenesis Contribute to Hepatotoxicity in HIV-Exposed Liver Cells.
New-Aaron, M, Thomes, PG, Ganesan, M, Dagur, RS, Donohue, TM, Kusum, KK, Poluektova, LY, Osna, NA
Biomolecules. 2021;(10)
Abstract
Although the causes of hepatotoxicity among alcohol-abusing HIV patients are multifactorial, alcohol remains the least explored "second hit" for HIV-related hepatotoxicity. Here, we investigated whether metabolically derived acetaldehyde impairs lysosomes to enhance HIV-induced hepatotoxicity. We exposed Cytochrome P450 2E1 (CYP2E1)-expressing Huh 7.5 (also known as RLW) cells to an acetaldehyde-generating system (AGS) for 24 h. We then infected (or not) the cells with HIV-1ADA then exposed them again to AGS for another 48 h. Lysosome damage was assessed by galectin 3/LAMP1 co-localization and cathepsin leakage. Expression of lysosome biogenesis-transcription factor, TFEB, was measured by its protein levels and by in situ immunofluorescence. Exposure of cells to both AGS + HIV caused the greatest amount of lysosome leakage and its impaired lysosomal biogenesis, leading to intrinsic apoptosis. Furthermore, the movement of TFEB from cytosol to the nucleus via microtubules was impaired by AGS exposure. The latter impairment appeared to occur by acetylation of α-tubulin. Moreover, ZKSCAN3, a repressor of lysosome gene activation by TFEB, was amplified by AGS. Both these changes contributed to AGS-elicited disruption of lysosome biogenesis. Our findings indicate that metabolically generated acetaldehyde damages lysosomes and likely prevents their repair and restoration, thereby exacerbating HIV-induced hepatotoxicity.
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9.
Modeling the Ethanol Tolerance of the Probiotic Yeast Saccharomyces cerevisiae var. boulardii CNCM I-745 for its Possible Use in a Functional Beer.
Ramírez-Cota, GY, López-Villegas, EO, Jiménez-Aparicio, AR, Hernández-Sánchez, H
Probiotics and antimicrobial proteins. 2021;(1):187-194
Abstract
Saccharomyces yeasts are able to ferment simple sugars to generate levels of ethanol that are toxic to other yeasts and bacteria. The tolerance to ethanol of different yeasts depends also on the incubation temperature. In this study, the ethanol stress responses of S. cerevisiae and the probiotic yeast S. boulardii CNCM I-745 were evaluated at two temperatures. The growth kinetics parameters were obtained by fitting the Baranyi and Roberts model to the experimental data. The four-parameter logistic Hill equation was used to describe the ethanol tolerance of the yeasts at the temperatures of 28 and 37 °C. Adequate determination coefficients were obtained (R2 > 0.91) in all cases. S. boulardii grown at 28 °C was selected as the yeast with the best ethanol tolerance (6-8%) for use in the elaboration of functional craft beers.
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10.
Alcohol and Cancer: Epidemiology and Biological Mechanisms.
Rumgay, H, Murphy, N, Ferrari, P, Soerjomataram, I
Nutrients. 2021;(9)
Abstract
Approximately 4% of cancers worldwide are caused by alcohol consumption. Drinking alcohol increases the risk of several cancer types, including cancers of the upper aerodigestive tract, liver, colorectum, and breast. In this review, we summarise the epidemiological evidence on alcohol and cancer risk and the mechanistic evidence of alcohol-mediated carcinogenesis. There are several mechanistic pathways by which the consumption of alcohol, as ethanol, is known to cause cancer, though some are still not fully understood. Ethanol's metabolite acetaldehyde can cause DNA damage and block DNA synthesis and repair, whilst both ethanol and acetaldehyde can disrupt DNA methylation. Ethanol can also induce inflammation and oxidative stress leading to lipid peroxidation and further DNA damage. One-carbon metabolism and folate levels are also impaired by ethanol. Other known mechanisms are discussed. Further understanding of the carcinogenic properties of alcohol and its metabolites will inform future research, but there is already a need for comprehensive alcohol control and cancer prevention strategies to reduce the burden of cancer attributable to alcohol.