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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.
Rheological stability of carbomer in hydroalcoholic gels: Influence of alcohol type.
Kolman, M, Smith, C, Chakrabarty, D, Amin, S
International journal of cosmetic science. 2021;(6):748-763
Abstract
OBJECTIVE The main objective of this paper is to analyse and attempt to understand the nature of rheological changes observed and the dynamics of Carbopol NF 980 hydroalcoholic gels neutralized specifically by triethanol amine (TEA), both as a function of time and alcohol type to probe time stabilities and ageing effects in such carbopol gel systems. The rheological changes and dynamics of 3 carbopol gel systems were observed; the gels included a water-based, ethanol-based, and isopropyl alcohol-based gel. It is hoped that this study shall shed light on the dynamical nature and the microstructural evolution of such networked gel systems, which were maintained under closed isothermal conditions and left completely unperturbed. The experimental results can provide the information necessary to understand and proposes plausible mechanisms guiding this dynamical behaviour in hydroalcoholic carbopol gels. METHODS A TA instrument mechanical rheometer was used to measure the viscosity and storage and loss modulus, and a pH meter was utilized to determine the changes in each sample over the period. RESULTS Studying the differences in the gel structures upon initial preparation illustrated that the ethanol and isopropyl alcohol (IPA) gels differed from the water-based gel in terms of viscosity, G', and G″, with the IPA gel displaying the lowest viscosity and moduli values across all shear rates. All the three gel systems exhibited strong shear thinning characteristics and were reminiscent of yield stress type found in colloidal gels. The water-based gel compared to the hydroalcoholic gels was strongly G' dominated, with the magnitude of the difference between G' and G″ observed to be much higher. This reflects that initial formation of the water-based gel structure possesses a much more rigid structure with a high elastic modulus component dominating. This also suggests that the water-based gel structure displayed stronger interactions between the carbopol particles when compared to those of the hydroalcoholic gels. Over the 30-day period, it was observed that the ethanol and water-based gels did not reveal any appreciable viscosity changes, with only an approximate 12% and 7% change from day 1 to 30, respectively. It was observed that the IPA systems' viscosity drastically increased over the period, with an approximately 77% change from day 1 to 30. The water and ethanol-based gels also exhibited very similar rheological behaviour over the entire time period with G' dominating G″. The G″ values of the water and ethanol-based gels decreased slightly at the end of day 30 by 10% and 16%, respectively, while the G' values for each sample remained essentially unchanged, increasing only 0.06% for the water-based gel, and increasing 1.4% for the ethanol-based gel. This further confirms the relatively stable gel structures attained. For the isopropyl gel system, the storage modulus of the system exhibited an average percent increase of approximately 16% from day 1 to day 30, but interestingly the loss modulus varied the least amongst all the gel systems, with only a 3% increase. The increase in G' reflects upon the evolution of a more rigid structure by day 30 for the IPA gel. This observation is clearly consistent with the corresponding increase in viscosity observed in the IPA gel. None of the gels tested displayed a consistent pH over the period. The pH of the hydroalcoholic gels was higher than that of the water-based gel for a majority of the period. The greatest fluctuations in pH were observed for the water and IPA gels, even though the water-based gel had one of the most stable rheological profiles out of the samples tested. The water, ethanol, and IPA gels' pH increased approximately 25%, 6%, and 5%, respectively, from day 1 to day 30. CONCLUSION The rheological and pH study of the 3 hand sanitizer systems over a 30-day period allowed for rational insights into the plausible reasons responsible for driving the observed rheological changes in these unperturbed systems. For the water-based gel, we hypothesize that the changes observed are due to physical ageing, where the gel structure has evolved over time to eventually progress towards a more stabilized framework structure. The pH of the gel upon formation was on the lower side. Such a lower pH influences the formation of a gel, which is comparatively less swollen and occupies a slightly lesser volume, and thereby points to a much less compacted gel network structure or alternatively, a more fluid structure. If the particles moved around more, the system was not initially in a state of low energy, causing increased particle movement, and in turn, physical ageing. This could be responsible for the development of a physically altered structure over time. The gel structure dynamically attempts to minimize its free energy by becoming more rigid, which has been observed as being manifested in the decrease of both the viscosity and the G″. For the hydroalcoholic gels, we conjecture that ageing observed was a result of chemical ageing, and the alcohol type employed in the preparation is primarily responsible for exhibiting this effect. The polarities of ethyl alcohol and isopropyl alcohol are key to the stabilization of such resultant network structures which get formed because of neutralization. It has been observed in previous studies that with decreasing polarity, there was an increase in the neutralization needed to obtain the development of a structure half as well developed as the final resultant structure. Isopropyl alcohol is a much less polar solvent compared to ethanol and water, and therefore required higher levels of TEA as the base to neutralize the system. We conjecture that the charged TEA cationic species had a greater propensity to get exchanged with bulk solution in the vicinity of the polymer into the bulk solution, and that the pH fluctuation observed indicated a kinetic exchange process over time, causing the viscosity and moduli profiles to increase along with the pH. At this time though, further investigations need to be carried out to truly understand the underlying instability, and thus dynamics for gel systems of this type.
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4.
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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5.
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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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.
Alcohol's Impact on the Fetus.
Popova, S, Dozet, D, Shield, K, Rehm, J, Burd, L
Nutrients. 2021;(10)
Abstract
BACKGROUND Alcohol is a teratogen and prenatal exposure may adversely impact the developing fetus, increasing risk for negative outcomes, including Fetal Alcohol Spectrum Disorder (FASD). Global trends of increasing alcohol use among women of childbearing age due to economic development, changing gender roles, increased availability of alcohol, peer pressure and social acceptability of women's alcohol use may put an increasing number of pregnancies at risk for prenatal alcohol exposure (PAE). This risk has been exacerbated by the ongoing COVID-19 pandemic in some countries. METHOD This literature review presents an overview on the epidemiology of alcohol use among childbearing age and pregnant women and FASD by World Health Organization regions; impact of PAE on fetal health, including FASD; associated comorbidities; and social outcomes. RESULTS/CONCLUSION The impact of alcohol on fetal health and social outcomes later in life is enormous, placing a huge economic burden on countries. Prevention of prenatal alcohol exposure and early identification of affected individuals should be a global public health priority.
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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.
Potential for reduced water consumption in biorefining of lignocellulosic biomass to bioethanol and biogas.
Yuan, HW, Tan, L, Kida, K, Morimura, S, Sun, ZY, Tang, YQ
Journal of bioscience and bioengineering. 2021;(5):461-468
Abstract
Increasing ethanol demand and public concerns about environmental protection promote the production of lignocellulosic bioethanol. Compared to that of starch- and sugar-based bioethanol production, the production of lignocellulosic bioethanol is water-intensive. A large amount of water is consumed during pretreatment, detoxification, saccharification, and fermentation. Water is a limited resource, and very high water consumption limits the industrial production of lignocellulosic bioethanol and decreases its environmental feasibility. In this review, we focused on the potential for reducing water consumption during the production of lignocellulosic bioethanol by performing pretreatment and fermentation at high solid loading, omitting water washing after pretreatment, and recycling wastewater by integrating bioethanol production and anaerobic digestion. In addition, the feasibility of these approaches and their research progress were discussed. This comprehensive review is expected to draw attention to water competition between bioethanol production and human use.
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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.