High-concentration Ethanol Research Articles

Key role of K+ and Ca2+ in high-yield ethanol production by S. Cerevisiae from concentrated sugarcane molasses

BackgroundSaccharomyces cerevisiae is an important microorganism in ethanol synthesis, and with sugarcane molasses as the feedstock, ethanol is being synthesized sustainably to meet growing demands. However, high-concentration ethanol fermentation based on high-concentration sugarcane molasses—which is needed for reduced energy consumption of ethanol distillation at industrial scale—is yet to be achieved.ResultsIn the present study, to identify the main limiting factors of this process, adaptive laboratory evolution and high-throughput screening (Py-Fe3+) based on ARTP (atmospheric and room-temperature plasma) mutagenesis were applied. We identified high osmotic pressure, high temperature, high alcohol levels, and high concentrations of K+, Ca2+, K+ and Ca2+ (K+&Ca2+), and sugarcane molasses as the main limiting factors. The robust S. cerevisiae strains of NGT-F1, NGW-F1, NGC-F1, NGK+, NGCa2+ NGK+&Ca2+-F1, and NGTM-F1 exhibited high tolerance to the respective limiting factor and exhibited increased yield. Subsequently, ethanol synthesis, cell morphology, comparative genomics, and gene ontology (GO) enrichment analysis were performed in a molasses broth containing 250 g/L total fermentable sugars (TFS). Additionally, S. cerevisiae NGTM-F1 was used with 250 g/L (TFS) sugarcane molasses to synthesize ethanol in a 5-L fermenter, giving a yield of 111.65 g/L, the conversion of sugar to alcohol reached 95.53%. It is the highest level of physical mutagenesis yield at present.ConclusionOur results showed that K+ and Ca2+ ions primarily limited the efficient production of ethanol. Then, subsequent comparative transcriptomic GO and pathway analyses showed that the co-presence of K+ and Ca2+ exerted the most prominent limitation on efficient ethanol production. The results of this study might prove useful by promoting the development and utilization of green fuel bio-manufactured from molasses.

The structure-activity relationship for the ABA triblock siloxane surfactant in aqueous-ethanol system

It is challenging to improve the foam stability in high concentration ethanol solution. In this paper, well-defined polyether-modified siloxane surfactants were synthesized, and their structures were characterized through infrared spectroscopy and one- and two-dimensional Nuclear magnetic resonance (NMR) spectroscopy. Furthermore, the relationships of between their chemical structure, surface activity, and foam property in high concentration ethanol solution were investigated in detail. The results showed that the target surfactant exhibited an ABA-type structure. They can effectively reduce the surface tension and produce the excellent foam in 75 % ethanol. In particular, these surfactants with loner siloxane chain confer strong foaming power in 75 % solution. This ability with good surface activity in water-ethanol system suggests a wide range of potential applications in low surface tension solvent system.

Measurement Of Ethanol Concentration in Liquid Organic Fertilizer Fermentation Emissions Using The MQ-8 Sensor

Ethanol is beneficial for the sterilization process and increases the rate of photosynthesis. Measurement of ethanol concentration is necessary because ethanol in high concentrations can cause several health problems, such as eye irritation, coughing, lacerations, and ineffective plant sterilization processes. Therefore, a sensor-based measurement system is needed to measure the total gas concentration in liquid organic fertilizer. This research aims to characterize the MQ-8 sensor and analyze the ethanol concentration for the fermentation process. The results of this study indicate that the MQ-8 sensor can work well in measuring the concentration of a single ethanol compound with an accuracy of 91%. The total concentration of ethanol gas in each sample liquid organic fertilizer is measured between 216 ppm to 1583 ppm, depending on the fermented plant.

Achieving efficient and rapid high-solids enzymatic hydrolysis for producing high titer ethanol with the assistance of di-rhamnolipids

High-solids enzymatic hydrolysis is the premise of obtaining high concentration ethanol by fermentation. In this study, corn stover was first pretreated with formic acid under mild conditions, and more than 70 % of xylan and lignin were removed within the first hour. 173.0 g/L glucose was achieved from total 30 % solid of the pretreated corn stover via fed-batch mode. Moreover, the glucose concentration rose to 194.5 g/L and the hydrolysis time was significantly reduced by 42.9 % with the addition of di-rhamnolipid. On this basis, 89.1 g/L ethanol was obtained by fermentation, and the presence of di-rhamnolipid had no negative effect on fermentation. The effective conversion of corn stover to high titer ethanol provides support for the conversion of stover to ethanol in industrial production.

PDMS-b-PI-b-PDMS triblock copolymer self-supported membranes with microphase separated structures for efficient ethanol dehydration

High concentration ethanol dehydration had attracted great attentions through membrane separation methodology in the past years, of which membrane is the key factor to decide the separation performance. In this paper, a series of novel self-supported membranes were prepared based on PDMS-b-PI-b-PDMS triblock copolymers by solution casting method. The composition and structure of the copolymers were confirmed by FTIR, GPC and 1HNMR. The self-supported dehydrated membranes showed good thermal, chemical, and mechanical stability. Their water contact angle decreased obviously from 96° to 61° with the increasing PI contents from 50% to 100% in the triblock copolymers. The clear microphase separation with continuous PI domains of PDMS-b-PI-b-PDMS based membranes were observed in the TEM image. The microphase domain size increased with the increasing of molecular weight and content of PDMS. The higher domain size resulted in lower flux and higher separation factor of these membranes. The membrane M3, which has 70 wt% of PI content in the triblock copolymer, exhibit excellent ethanol dehydration performance with flux of 3.96 kg·m−2·h−1, separation factor of 255 and maintained 120 h with barely decreasing in separation performance, for 95 wt% ethanol solution at 20 °C. When elevated the feed temperature upto 60 °C, the dehydration flux increased to 16.90 kg·m−2·h−1, and the separation factor decreased to 37. Membranes with microphase separation have great potential application in the ethanol dehydration.

Structural Design and Preparation Process Research of Stacked MEMS Gas Sensors for Volatile Organic Compound Gases

To design gas sensors with fast response speed and high sensitivity for the detection of volatile organic compounds, a stacked MEMS sensor was designed in this study. It utilizes porphyrin-sensitive materials and carbon nanotubes to form composite materials, improve the thermal stability of sensitive materials, and conduct sensor gas sensitivity testing. The results show that the design of the thermal insulation structure makes the sensor obtain lower power consumption and more uniform temperature distribution, and the maximum deformation variable is 3.7 × 10−2 μM. Doping carbon nanotubes in porphyrin-sensitive materials can effectively improve their thermal stability, and the sensor is in a safe state at temperatures below 358 °C. The sensor with higher response recovery characteristics at a low concentration of 80 ppm aniline has better response recovery characteristics, with a response time of 33 s and a recovery time of 23 s, respectively; its response recovery characteristics to 1% high concentration ethanol gas are good, with a recovery time of 13 s and a sensitivity of 1.05. In the analysis of the sensor image characteristics, when the Euclidean distance threshold is set to five, four gases such as aniline and formaldehyde can be classified. The sensor designed in this study can effectively detect four gases, including aniline and formaldehyde.

Genetic diversity and some biological characteristics of antibacterial yeasts isolated from natural honey and beeswax in Son La province

Yeast living in honey, an environment with high sugar content (up to 70 %, w/v), normally shows good resistance to the high level of osmotic pressure; they are of high potential for application in many fields. There were not many studies on the genetic diversity and biological characteristics of yeast from honey in Vietnam. This study aims to (1) evaluate the genetic diversity of antibacterial yeast isolated from natural honey and beeswax in Son La province by RAPD (Random Amplified Polymorphic DNA) and (2) study some biological characteristics of them. The research results may contribute to the scientific basis for screening yeast strains applied in different fields such as bioethanol and probiotic production. Sixty-eight yeast strains were isolated from natural honey and beeswax collected in Son La. Among them, twenty-one strains showed antibacterial activity against at least a tested bacterium including Escherichia coli, Bacillus subtilis, and Serratia marcescens. These yeast strains were genetically distinct in the RAPD analysis using M13 and (GTG)5 primers. Evaluation of yeast growing in the medium containing high glucose concentration (30 - 40 %, w/v) or high ethanol concentration (5 - 10 %, v/v) has shown some yeast strains that can tolerate high osmotic pressure and high ethanol concentration for different applications. YC.8 and YC.61 strains exhibited relatively good survival rates in two phases of digestion and have a wide pH range (2 - 7). YC.8 strain expressed the most potential for human or animal probiotics.

Efficient production of high concentration monosaccharides and ethanol from poplar wood after delignification and deacetylation

Efficient enzymatic hydrolysis is required for the production of high concentration monosaccharides and ethanol. The lignin and acetyl group in poplar can limit the enzymatic hydrolysis. However, the effect of delignification combined with deacetylation on the saccharification of poplar for high concentration monosaccharides was not clear. Herein, hydrogen peroxide-acetic acid (HPAA) was used for delignification and sodium hydroxide was used for deacetylation to enhance the hydrolyzability of poplar. Delignification with 60% HPAA at 80 °C could remove 81.9% lignin. Acetyl group was completely removed with 0.5% NaOH at 60 °C. After the saccharification, 318.1 g/L monosaccharides were obtained with a poplar loading of 35% (w/v). After simultaneous saccharification and fermentation, 114.9 g/L bioethanol was gained from delignified and deacetylated poplar. Those results showed the highest monosaccharides and ethanol concentrations in reported research. This developed strategy with a relatively low temperature could effectively improve the production of high concentration monosaccharide and ethanol from poplar.

Rapid hydrolysis of PET in high-concentration alcohol aqueous solution by pore formation and spontaneous separation of terephthalate

Recovery of terephthalic acid (TPA) from waste polyethylene terephthalate (PET) should overcome the long-existing issues of low operation efficiency or massive wastewater generation during the hydrolysis and subsequent separation process to balance economics and environmental friendliness. Here, a high-concentration ethanol aqueous solution of 90 vol% is developed to achieve high-efficiency hydrolysis of PET by selectively cleaving C-O bonds and spontaneous separation of terephthalate using KOH as catalyst at 80 °C for 60 min. More than 98 % of TPA is recovered. It was attributed to the accelerated diffusion of the solvent in a reflux state due to the pore formation in PET and improved wettability between the solvent and PET. Notably, the terephthalate precipitated automatically from the reaction system due to low solubility in the solvent and separated by simple filtration, which avoids a large amount of waste water and acid in the following neutralization of terephthalate. The high efficiency of recycled reaction solution remained within several successive runs. The hydrolysis system is also applicable for degradation of other polymers containing ester groups and shows combined advantages of simplicity, high efficiency and eco-friendliness.

Acquired resistance to severe ethanol stress-induced inhibition of proteasomal proteolysis in Saccharomyces cerevisiae

BackgroundAlthough the budding yeast, Saccharomyces cerevisiae, produces ethanol via alcoholic fermentation, high-concentration ethanol is harmful to yeast cells. Severe ethanol stress (> 9% v/v) inhibits protein synthesis and increases the level of intracellular protein aggregates. However, its effect on proteolysis in yeast cells remains largely unknown. MethodsWe examined the effects of ethanol on proteasomal proteolysis in yeast cells through the cycloheximide-chase analysis of short-lived proteins. We also assayed protein degradation in the auxin-inducible degron system and the ubiquitin-independent degradation of Spe1 under ethanol stress conditions. ResultsWe demonstrated that severe ethanol stress strongly inhibited the degradation of the short-lived proteins Rim101 and Gic2. Severe ethanol stress also inhibited protein degradation in the auxin-inducible degron system (Paf1-AID*-6FLAG) and the ubiquitin-independent degradation of Spe1. Proteasomal degradation of these proteins, which was inhibited by severe ethanol stress, resumed rapidly once the ethanol was removed. These results suggested that proteasomal proteolysis in yeast cells is reversibly inhibited by severe ethanol stress. Furthermore, yeast cells pretreated with mild ethanol stress (6% v/v) showed proteasomal proteolysis even with 10% (v/v) ethanol, indicating that yeast cells acquired resistance to proteasome inhibition caused by severe ethanol stress. However, yeast cells failed to acquire sufficient resistance to severe ethanol stress-induced proteasome inhibition when new protein synthesis was blocked with cycloheximide during pretreatment, or when Rpn4 was lost. Conclusions and general significanceOur results provide novel insights into the adverse effects of severe ethanol stress on proteasomal proteolysis and ethanol adaptability in yeast.

One-step synthesis of CdS hierarchical microspheres and its ethanol sensing property

The high concentration (>100 ppm) ethanol gas that CdS sensors detect commonly results in saturation problem. In this work, CdS hierarchical microspheres with the diameter of 5 µm–10 µm assembled with abundant nanosheets are prepared by a facile one-step solvothermal process. The specific surface area of the CdS material was 27.04 m2·g−1, which can provide a certain amount of active sites for the target gas and the adsorbed oxygen. In addition, the sensor fabricated by CdS hierarchical microspheres exhibits enhanced sensitivity for C2H5OH to 10 ppm at the optimum operating temperature of 200 °C. The sensor also shows good repeatability, excellent stability and fast response/recovery time of 2.8 s/4.8 s for C2H5OH to 100 ppm. Meanwhile, the good linear relationship of the sensor under wide concentration range of 10 ppm–500 ppm for C2H5OH demonstrates outstanding humidity resistance. The possible C2H5OH-sensing mechanism of CdS hierarchical microspheres is discussed on the basis of XPS analysis.

Exploration of nanofiltration conditions for separation of alcohol precipitation liquid during preparation of Reduning Injection by Box-Behnken design combined with flux attenuation

This study employed Box-Behnken design combined with flux attenuation to explore the nanofiltration conditions for separation of alcohol precipitation liquid during the preparation of Reduning Injection and discussed the applicability of nanofiltration in the separation of the liquid with high-concentration ethanol. The effects of nanofiltration molecular weight cut-off(MWCO) and pH on the rejection of chlorogenic acid, 3,5-dicaffeoylquinic acid, and 4,5-dicaffeoylquinic acid were consistent with the principles of pore size sieving and charge effect, respectively. The rejection of the three phenolic acids was reduced by concentration polarization effect caused by trans-membrane pressure(TMP). The swelling of membrane surface decreased the pore size and membrane flux for effective separation. Chlorogenic acid and 4,5-dicaffeoylquinic acid were more sensitive to pH and ethanol concentration than 3,5-dicaffeoylquinic acid. A certain correlation existed between the compound structure and the separation factors of nanofiltration, and the separation rules were associated with the comprehensive effect of charge effect, pore size sieving, concentration polarization, steric hindrance and so on.

Genetic Engineering Production of Ethyl Carbamate Hydrolase and Its Application in Degrading Ethyl Carbamate in Chinese Liquor.

Ethyl carbamate (EC), classified as a Group 2A carcinogen, is most abundant in the fermented foods, such as Cachaca, Shaoxing wine, and Chinese liquor (baijiu). Although biodegradation can reduce its concentration, a high ethanol concentration and acidic environment often limit its degradation. In the present study, a novel ethyl carbamate hydrolase (ECH) with high specificity to EC was isolated from Acinetobacter calcoaceticus, and its enzymatic properties and EC degradability were investigated. ECH was immobilized to resist extreme environmental conditions, and the flavor substance changes were explored by gas chromatography-mass spectrometry (GC/MS). The specific enzymatic activity of ECH was 68.31 U/mg. Notably, ECH exhibited excellent thermal stability and tolerance to sodium chloride and high ethanol concentration (remaining at 40% activity in 60% (v/v) ethanol, 1 h). The treatment of immobilized ECH for 12 h decreased the EC concentration in liquor by 71.6 μg/L. Furthermore, the immobilized ECH exerted less effect on its activity and on the flavor substances, which could be easily filtrated during industrial production.

Sensitive detection of glyoxal by cluster-mediated CH2Br2+ chemical ionization time-of-flight mass spectrometry

Direct and rapid analysis of glyoxal by soft ionization mass spectrometry remains a great challenge due to its low ionization efficiency in existing soft ionization techniques, such as proton transfer reaction (PTR) and photoionization (PI). In this work, we developed a new VUV lamp-based cluster-mediated CH2Br2+ chemical ionization (CMCI) source for time-of-flight mass spectrometry (TOFMS), which was accomplished by employing photoionization-generated CH2Br2+ as the reactant ion and co-sampling of glyoxal with high-concentration ethanol (EtOH). The signal intensity of glyoxal could be enhanced by more than 2 orders of magnitude by generating protonated cluster ion [Glx·EtOH·H]+. Density function theory (DFT) calculations was performed to obtain the most stable structure of neutral glyoxal-ethanol cluster and confirm that the ionization energy (IE) of glyoxal-ethanol cluster was significantly lower than that of glyoxal and CH2Br2 molecules, which makes it possible for effective ionization of glyoxal. The ionization efficiency of glyoxal could be dramatically enhanced via ion-molecule reaction between CH2Br2+ and glyoxal-ethanol cluster, as larger ionization cross section of glyoxal-ethanol cluster than glyoxal molecule might be achieved. The cluster-mediated signal enhanced effect was also verified by using other alcohols, such as methanol and isopropanol. Consequently, the limit of quantitation (LOQ, S/N = 10) down to 0.17 ppbv for gas-phase glyoxal was achieved. The analytical capacity of this system was demonstrated by trace analysis of glyoxal in food contact papers, exhibiting new insights and wide potentials of chemical ionization and photoionization mass spectrometry for VOCs measurement with higher sensitivity and wider detectable sample range.

Neonatal acute ethanol intoxication during the epidemic of COVID-19: a case report

BackgroundAfter the outbreak of COVID-19, many families equip with 75% ethanol to inactivate the SARS-CoV-2, which increases the risk of exposure to ethanol.Case presentationWe reported a 25-day-old newborn who was diagnosed with neonatal acute ethanol intoxication with a presenting complaint of accidental consumption about 15 ml formula milk containing 75% ethanol. His main clinical manifestations were irritability, flushed skin, tachycardia, tachypnea, and toxicology analysis detected ethanol. After timely gastric lavage and intravenous fluid replacement, he was cured and discharged.ConclusionsDuring the COVID-19 epidemic, high concentration ethanol used for inactivating SARS-COV-2 should be placed reasonably and neonatal feeding safety should be emphasized. Timely diagnosis and symptomatic treatment are essential for the prevention and management of acute ethanol intoxication in newborns.

Chronic Low-Dose Alcohol Consumption Promotes Cerebral Angiogenesis in Mice.

Chronic alcohol consumption dose-dependently affects the incidence and prognosis of ischemic stroke. We determined the influence of chronic alcohol consumption on cerebral angiogenesis under physiological conditions and following ischemic stroke. In in vitro studies, acute exposure to low-concentration ethanol significantly increased angiogenic capability and upregulated vascular endothelial growth factor A (VEGF-A) and vascular endothelial growth factor receptor 2 (VEGFR2) in C57BL/6J mouse brain microvascular endothelial cells (MBMVECs). The increased angiogenic capability was abolished in the presence of a VEGFR2 inhibitor. In addition, the increased angiogenic capability and upregulated VEGF-A and VEGFR2 remained in chronically low-concentration ethanol-exposed MBMVECs. In in vivo studies, 8-week gavage feeding with low-dose ethanol significantly increased vessel density and vessel branches and upregulated VEGF-A and VEGFR2 in the cerebral cortex under physiological conditions. Furthermore, vessel density, vessel branches, and expression of VEGF-A and VEGFR2 in the peri-infarct cortex were significantly greater in low-dose ethanol-fed mice at 72 h of reperfusion. Although low-dose ethanol did not alter cerebral vasoreactivity and regional cerebral blood flow (rCBF) either before or during ischemia, it significantly augmented post-ischemic hyperemia during reperfusion. In contrast, exposure to high-concentration ethanol and 8-week gavage feeding with high-dose ethanol only had a mild inhibitory effect on angiogenic capability and cerebral angiogenesis, respectively. We conclude that heavy alcohol consumption may not dramatically alter cerebral angiogenesis, whereas light alcohol consumption significantly promotes cerebral angiogenesis.

(Invited) Bio-Sniffers & Sniff-Cam: Biofluorometirc Gas Sensor and Imaging System for Human Volatile Chemicals

Introduction Various volatile organic compounds exist, such as those the transpired by humans, breath, body odor and smell of the living environment. The human body emits various volatile molecules, depending on a person’s genetics, disease and metabolic condition. In this contribution, novel gas-phase biosensors (bio-sniffer and sniff-cam) using bio-fluorometric techniques for human volatiles will be introduced as a future biosensing approach for preemptive medicine and healthcare. Bio-sniffer for breath acetone as early screening approach of diabetes mellitus. Secondary alcohol dehydrogenase (S-ADH) catalyzes the reduction of acetone and the oxidation of nicotinamide adenine dinucleotide (NADH to NAD+) in a weak acid environment (Fig.1). NADH is excited by 340 nm excitation lights and subsequently emit 490 nm fluorescence. Therefore, acetone can be measured by the decrease in NADH fluorescence intensity. A bio-fluorometric acetone sniffer was constructed by incorporating an optic-probe into a gas/liquid flow cell with S-ADH immobilized diaphragm (Fig.2) [1,2]. The developed biosniffer show rapid response, highly sensitivity and selectivity to acetone. The breath acetone analysis in healthy subjects shows that the mean values were 750.0 ± 434.4 ppb. The breath acetone did not show a statistical difference among different genders and ages. The breath acetone analysis for diabetic patients under medical treatment shows a mean value of 1207.7 ± 689.5 ppb, which was higher than that of healthy subjects (p < 1 × 10−6). In particularly, type-1 diabetic (T1D) patients exhaled a much higher concentration of acetone than type-2 diabetic (T2D) patients (p < 0.01) (Fig.3). These findings are worthwhile in the study of breath biomarkers for early screening of diabetes mellitus. Additionally, the developed bio-sniffers provide a new technique for volatolomics research. Sniff-cam with biofluorometric technique for spatiotemporal gas imaging A decade ago, a chemiluminescence sniff-cam system was developed and applied successfully for distribution imaging of high concentration ethanol vapor (ppm-level) such as breath ethanol after drinking (Fig.4) [3] and wine aroma from wine glass (Fig.5) [4]. In order to improve the performance, we applied the bio-fluorometric technique for highly sensitive sniff-cam system (ppb-level). The sniff-cam with ADH (alcohol dehydrogenase) redox reactions can show a spatiotemporal change of gaseous ethanol (EtOH) or acetaldehyde (AcH) in real-time [5,6]. The sniff-cam was composed of a highly sensitive camera, a UV-LED array sheet, and an ADH-immobilized mesh. The both redox reactions of ADH were employed for detection of gaseous EtOH and AcH where a relationship between fluorescence intensity from nicotinamide adenine dinucleotide. Moreover, the image differentiation method that calculated a fluorescence change rate was employed to visualize a real-time change in the concentration distribution of EtOH and AcH. The dynamic ranges of the sniff-cam for EtOH and AcH were 20ppb-300ppm and 100 ppb-10 ppm. As the physiological application, the sniff-cam successfully achieved the imaging of the concentration distribution of EtOH and AcH in breath and skin gas (Fig. 6). Future potential of the gas-phase biosensors (bio-sniffer and sniff-cam) The future potential of the bio-sniffer and sniff-cam for body volatiles includes the early disease screening, the identification of those locations, the real time evaluation of metabolic condition as a Bio-IoT monitoring.

Ethanol induces necroptosis in gastric epithelial cells in vitro.

The stomach frequently suffers from acute gastric diseases after excessive ingestion of high-concentration alcoholic beverages, but little is known about the pathological mechanism by which ethanol affects the gastric mucosa. The aim of this study was to explore the mechanism of gastric epithelial cell death induced by relatively high concentrations of ethanol in vitro. Ethanol was demonstrated to induce rapid cell death in a concentration-dependent manner (Spearman r=.943, p=.017) and to activate the phosphorylation of key mediators in necroptosis pathway without influencing the key mediators in apoptosis pathway. The receptor-interacting serine-threonine kinase 1 (RIP1) kinase inhibitor necrostatin-1s (nec-1s) was found to reverse necroptotic cell death (from 65.5% necrosis to 35.8% necrosis, p=.006) and to inhibit the formation of necrosome complexes. These results indicate necroptosis rather than apoptosis pathway is an essential mechanism and is a novel therapeutic target in acute alcoholic gastric diseases. PRACTICAL APPLICATIONS: Alcohol consumption is related with a variety of diseases in many organs, but its pathological mechanism might be quite different due to the exposure extent between the stomach and other organs. Although there have been plenty of studies on alcoholic liver diseases and those in other organs, the pathological mechanism of alcoholic gastric diseases has been poorly investigated. Considering the unique distribution of ethanol on gastric mucosa, it is worthwhile to explore the specific cell death pattern of gastric epithelial cells under high-concentration ethanol treatment. Further investigation of the mechanisms of alcoholic gastric diseases would provide potential therapeutic strategies for the treatment of acute alcoholic gastric diseases as well as other acute alcoholic diseases.

Screening yeast strains for alcohol fermentation from the dried traditional yeast

Methods to produce rice alcohol by dried traditional yeast are unstable because the yeast system in dried traditional yeast has depended on nature and not been controlled. In this study, a total of 15 different kinds of dried traditional yeast were prepared and screened. Each yeast strain was evaluated by analyzing its fermentation property and alcohol tolerance. There are 19 yeast strains were isolated and their growth conditions and ethanol producing properties were examined. Results showed that three strains S1, BT, BL3 grew and produced ethanol at temperature 28-30oC, and pH 5-5.5. Especially, high concentration ethanol tolerance ability of the three strains was at 8-18%. Our results showed that these strains were valuable microorganisms and could be utilized as a basis for further study of dried traditional yeast in traditional alcoholic beverages.

Comprehensive emission characterisation of exhaust from alternative fuelled cars

Abstract Exhaust emissions from Euro 2-6a cars using diesel, gasoline, high concentration ethanol (E85) fuel and compressed natural gas (CNG) were studied comprehensively, with a focus on results obtained at −7 °C test temperature. Higher emissions than desired were noticed in some cases, e.g. elevated methane emissions from natural gas fuelled cars, as well as methane and acetaldehyde emissions from E85 fuelled flexible fuel vehicles. Additionally, mutagenicity of PM samples and oxidative potential of semivolatile samples were observed. However, emission performance improved significantly when moving from older to newer Euro 6a cars, showing that low tailpipe exhaust emissions can be achieved when combining new car technology with CNG, E85, gasoline and diesel fuels. Furthermore, the climate impact of these technologies could reduce by using renewable counterparts of these fuels.