Insoluble Solids Content Research Articles

Physico-chemical Properties and Biological Activity of Honey from Two Districts of Tien Giang Province, Vietnam

This study was conducted to determine the physico-chemical properties and biological activity of honey collected from the Tan Phu Dong and Cai Be districts of Tien Giang province, Vietnam. The results showed that the 19% and 20% moisture content honey from Tan Phu Dong district had viscosities of 1075 Cp and 1013.33 Cp, insoluble solid contents of 0.12% and 0.09%, acidities of 32.49 mg/1000 g and 30.49 mg/1000 g, diastase index of 4.5 Schade and 4.09 Schade, free reducing sugar content of 65% and 67%, HMF contents of 0.98 mg/100 g and 0.86 mg/100 g and antioxidant activity of 0.47 and 0.52 mg vitamin C equiv./mg dry wt, respectively. The honey from Cai Be district with 22% moisture content, viscosities, insoluble solid content, acidity, diastase index, free reducing sugar, HMF content and DPPH antioxidant activity displayed as 619 Cp, 0.119%, 46.41 mg/1000 g, 5 Schade, 60.28%, 0.38 mg/100 g and 0.45 mg vitamin C equiv./mg dry wt, respectively.

Cercetări privind stabilirea unor legături dintre compoziția și procesul de structurare a fructelor-snack-uri

The article presents the experimental work results analysis concerning the study of structuring of fruit puree with different content of insoluble solids. Structuring has been carried out in the process of puree dehydration to different values of water activity, which are in the range of 0.38-0.78. Correlations between water activity (aw) and moisture content, and dependences between aw and insoluble solids content have been established for the studied products of different quality. Graphical dependences of the quality organoleptic evaluation on water activity, the content of water-insoluble solids (Inap) and alcohol-insoluble solids (Inal) have been presented for the structured purees. The most favorable ranges of aw, Inap, Inal for fruit puree structuring have been determined.

The properties and formation mechanism of ovalbumin-fucoidan complex

The polymeric materials formed by proteins and polysaccharides through molecular interactions have attracted public attention. In this study, a novel binary complex consisting of ovalbumin (OVA) and fucoidan (FUC) was obtained by electrostatic self-assembly. The self-assembly properties and the formation mechanism of the OVA-FUC binary complex were investigated by changing the charging degree and density of complex through altering pH value and polysaccharides proportion. Structural changes during the OVA-FUC electrostatic self-assembly process were investigated by a phase diagram, ζ-potential, and particle size. The optimal conditions for preparing soluble OVA-FUC binary complex were determined by the protein retention rate and insoluble solids content. Results showed that the soluble OVA-FUC binary complex could be obtained at the pH of 3.5 to 5, and the insoluble OVA-FUC binary complex was generated at the pH of 2.5 to 3.5. The OVA-FUC binary complex (19 ± 0.29 mN/m) possessed a medium ability to reduce interfacial tension of the water-oil interface compared with OVA (15 ± 1.13 mN/m) and FUC (24 ± 0.3 mN/m), indicating that OVA-FUC binary complex has good amphiphilicity and can be applied as a potential pH-controlled emulsifier in function food systems for delivering bioactive substances.

Research on the Formulation System of Weak Gel and the Influencing Factors of Gel Formation after Polymer Flooding in Y1 Block

After long-term polymer flooding, water channeling, and ineffective water circulation occur in oil wells, which seriously affect polymer flooding efficiency and oilfield recovery. The weak gel system has the property of delaying cross-linking. After the weak gel system enters the deep formation, the cross-linking reaction is carried out, which can achieve the purpose of deep regulation and flooding. In this paper, according to the formation characteristics of high temperature, high permeability, and large pores in Y1 block (a block in the Daqing Yushulin Oilfield), the formulation of weak gel system was developed. The optimal formulation was determined by parameters such as gel-forming properties, stability, viscoelasticity, and rheology. Finally, the best formulation for the Y1 block is that containing 0.22% of polyacrylamide (HPAM) and 0.15% of chromium (III) acetate system. The gel-forming time of the formulation is 8 h, and the viscosity can be maintained at 15,000–24,000 mPa·s. Next, this paper studied the factors that affect the gelation of formulations, mainly including dissolved oxygen content, bacterial content, insoluble suspended solids content, and metal ions in the formulation water. The results show that the critical point of the worst effect is the oxygen content close to 1.5 mg/L, and the optimal critical point of oxygen content of the gel system is 7 mg/L. The bacteria in the prepared water degrade the weak gel solution. The more bacteria, the more serious the degradation of the weak gel. A small amount of insoluble suspended solids will greatly increase the viscosity of the weak gel solution, but will accelerate the gel-breaking time. When the content of insoluble suspended solids is high, more than 1000 mg/L, a precipitate will be formed at the bottom of the solution, and the difference in the content of insoluble suspended solids in this interval has little effect on weak gels. The metal ion that mainly affects the gelation effect is Fe2+. With the increase of Fe2+ mass concentration, the viscosity of weak gel decreases sharply.

Turbidity characterization as a decision-making tool for extra virgin olive oil stability treatments

The extra virgin olive oil (EVOO) commercialized by olive oil companies usually has highly variable turbidity characteristics. Ten veiled EVOOs with different water content, insoluble solid content, water activity, degree of turbidity, and microbial cell count, and their respective filtered samples, were studied both to assess the risk of degradation phenomena and to suggest a rapid method to measure oil quality stability. The EVOO samples were analyzed for legal parameters, phenolic compounds, volatile organic compounds, and sensory attributes, immediately after purchase and after 45 and 180 days of storage at room temperature in dark conditions. A statistically significant relationship was found between water content and oil degradation during storage; hydrolytic phenomena and microbial spoilage occurred, causing variations in the oil quality in terms of phenolic compound hydrolysis, fusty and fruity sensory attributes, and volatile compound content. A > 0.2 %w/w water content value was measured as predicting a high risk of oil degradation. Moreover, since the research determined an original relationship between water content and NTU, we proposed that olive oil companies should adopt the following decision-making approach: EVOO with NTU values > 100–200 should be subjected to a schedule of treatments that reduce water content in a short time.

Effect of temperature on the rheology of concentrated suspensions containing lignocellulosic biomass particles

Apparent viscosities of Wiley milled white birch at various particulate sizes, suspension concentrations, and solvent and acid concentrations were measured as a function of temperature. Apparent viscosities decreased reversibly with increasing temperature below 150 °C in water in the absence of acid and/or solvent. At temperatures above 150 °C, or with added solvent or acid, the variation of the apparent viscosities with temperature became irreversible. The steady-state shear dependent behavior is well described by a Bingham model where the yield stress is a strong function of temperature and follows an Arrhenius-type behavior. The suspensions exhibited a negative plastic viscosity at low temperatures, but as the temperature increased, the plastic viscosity became less negative. This temperature dependent rheological behavior is qualitatively similar to that observed for concentrated fibrous suspensions of corn stover and synthetic fibers, indicating these changes are not unique to only birch suspensions and are associated with physical changes in the suspension properties with temperature. The irreversible viscosity changes with increase in temperature above 150 °C in water were anticipated due to partial hydrolysis of biomass in water. This was confirmed when biomass suspensions were sheared in a polar aprotic solvent (γ-valerolactone) and/or with the addition of sulfuric acid. Finally, the extent of irreversible change in the viscosities was correlated with the change in insoluble solids concentration for the various experiments under different conditions.

Investigation of Rheological Behavior of Untreated and Microwave-Assisted Alkaline Pretreated Sugarcane Straw for Biofuel Production

Biomass slurries, such as those subjected to microwave-assisted alkaline (MAA) pretreatment, will become common substrates for the production of biofuels in the future. While the rheology of acid and ionic liquid pretreated biomass is known, the rheology of alkaline pretreated biomass is not yet reported; hence, the goal of this study was to establish the rheological characteristics of untreated and MAA pretreated sugarcane straw (SC). Using rotational rheometry and rheological models, the rheology of SC slurries was assessed as a function of particle size and insoluble solids concentration. In the range of 5–17% insoluble solids concentration, the slurries were consistently pseudo-plastic (n = 0.33 ± 0.02), possessed yield stress with their flow accurately described by the Casson rheological model (R2 = 0.98–0.99). The apparent viscosity and yield stress increased by two orders of magnitude with an increase in insoluble solids concentration. Essentially, MAA pretreated slurries exhibited significantly higher values of apparent viscosity and yield stress than the untreated ones, in the range of 55–80% and 21–63% for particle sizes of < 63 µm (P63) and 90–180 µm (P90), respectively. Pretreated P63 samples exhibited higher apparent viscosity and yield stress than the P90. On the other hand, for untreated samples, P63 samples had a reduced apparent viscosity than P90 samples. The results of this study definitively reveal that MAA significantly increases the shear rate dependent shear viscosity values along with the yield stress of biomass slurries. This will, therefore, serve as a benchmark for characterizing other MAA pretreated biomass slurries to guide the design of industrial-scale production equipment.

A two-phase substrate model for enzymatic hydrolysis of lignocellulose: application to batch and continuous reactors

BackgroundEnzymatic hydrolysis continues to have a significant projected production cost for the biological conversion of biomass to fuels and chemicals, motivating research into improved enzyme and reactor technologies in order to reduce enzyme usage and equipment costs. However, technology development is stymied by a lack of accurate and computationally accessible enzymatic-hydrolysis reaction models. Enzymatic deconstruction of cellulosic materials is an exceedingly complex physico-chemical process. Models which elucidate specific mechanisms of deconstruction are often too computationally intensive to be accessible in process or multi-physics simulations, and empirical models are often too inflexible to be effectively applied outside of their batch contexts. In this paper, we employ a phenomenological modeling approach to represent rate slowdown due to substrate structure (implemented as two substrate phases) and feedback inhibition, and apply the model to a continuous reactor system.ResultsA phenomenological model was developed in order to predict glucose and solids concentrations in batch and continuous enzymatic-hydrolysis reactors from which liquor is continuously removed by ultrafiltration. A series of batch experiments were performed, varying initial conditions (solids, enzyme, and sugar concentrations), and best-fit model parameters were determined using constrained nonlinear least-squares methods. The model achieved a good fit for overall sugar yield and insoluble solids concentration, as well as for the reduced rate of sugar production over time. Additionally, without refitting model coefficients, good quantitative agreement was observed between results from continuous enzymatic-hydrolysis experiments and model predictions. Finally, the sensitivity of the model to its parameters is explored and discussed.ConclusionsAlthough the phenomena represented by the model correspond to behaviors that emerge from clusters of mechanisms, and hence a set of model coefficients are unique to the substrate and the enzyme system, the model is efficient to solve and may be applied to novel reactor schema and implemented in computational fluid dynamics (CFD) simulations. Hence, this modeling approach finds the right balance between model complexity and computational efficiency. These capabilities have broad application to reactor design, scale-up, and process optimization.

Characterization of Zygophyllum album L Monofloral Honey from El-Oued, Algeria

Background: Honey is generally evaluated by physicochemical analysis of its constituents. The manipulation of honey and its possible adulteration is reflected in many of its physicochemical properties. Objective: In this study, samples of Zygophyllum album L honey produced in El-Oued, Algeria, were characterized based on their melissopalynology, physicochemical and antioxidant properties, also polyphenol content. Methods: The physicochemical parameters of honey, such as density, moisture content, pH, free acidity, electrical conductivity (EC), total sugar content, color intensity, water insoluble solids content, hydroxymethylfurfural (HMF), ash, specific rotation, were measured. A number of antioxidant tests were performed to determine the antioxidant properties of Zygophyllum album L honey samples. The polyphenol in the Zygophyllum album L honey was measured by spectrometric determination based on folin-ciocalteu’s method. The identification and quantification of phenolic compounds were carried out by RP-HPLC (high-performance liquid chromatography). Results: All honey samples contained monofloral (67.83-91.89%) pollen belonging to Zygophyllum album L. The results of physicochemical parameters of analyzed honeys were: pH 4.33, moisture 17.2%, free acidity 41.96 meq/kg, electrical conductivity 0.408 mS/cm, HMF 11.89 mg/kg, Ash 0.246 (%), specific rotation -8.21. The Zygophyllum album L honey was extra white amber. The total sugar content ranged from 81.5 to 83. Honey samples contain high levels of gallic acid (252.53±15.56 mg/kg honey), chlorogenic acid (124.71±10.09 mg/kg) and low amounts of total polyphenol (467.82±46,98 mg GAE/kg). Conclusion: Physicochemical parameters (total acidity, pH, moisture, dry matter, ash, and qualitative hydroxymethylfurfural) were within the approved limits established by International Honey Commission.

Determinación de la calidad físico-química de la miel de abeja comercializada en Quito y comparación con la miel artificial

Se evaluó la calidad de 27 muestras de miel de abeja que se comercializa en los mercados del sur de Quito mediante los análisis físico-químicos establecidos como requisitos en la Norma NTE INEN 1572-1988. Los resultados obtenidos se compararon con los mismos análisis realizados en una muestra de miel artificial. Los métodos utilizados para cada determinación analítica fueron: AOAC 962.37 para densidad, AOAC 962.19 para humedad, AOAC 52.729 para acidez, AOAC 945.79 para sólidos insolubles, AOAC 920.181 para cenizas, AOAC 980.23 para hidroximetilfurfural, AOAC 958.09 para diastasa y el método de Luff-Schoorl para la determinación de azúcares. Con excepción de una muestra que no cumplió el valor máximo del parámetro del contenido de hidroximetilfurfural, y tres muestras que no cumplieron con el porcentaje de azúcares reductores, toda la miel de abeja analizada cumplió con los requisitos de la norma, aunque presentaron resultados con diferencias significativas en varios parámetros entre las diferentes marcas. En cuanto a la comparación de la miel de abeja con la miel artificial existió diferencia significativa en el contenido de sólidos t en agua, azúcares reductores, sacarosa e hidroximetilfurfural, y la actividad de la diastasa.

Textural character of sweet potato root of Korean cultivars in relation to chemical constituents and their properties.

A relationship between chemical constituents and physicochemical and textural properties of different Korean sweet potato (SP) cultivars were investigated in terms of the hardness of raw and cooked root, alcohol insoluble solid (AIS), starch and amylose content, amylase activities, and pasting properties. Correlation coefficients were analyzed and principal component analysis was performed. The hardness of cooked root was found to correlate with the hardness ratio of cooked/raw SP, AIS content (0.75**), starch content (0.64**), and peak viscosity of SP powder (0.56*). It was discovered that SP cultivars could be classified into mealy (Sincheonmi, Daeyumi, Sinyulmi), intermediate (Dahomi, Sinjami, Geonhwangmi, Yeonjami, Pungwonmi), and waxy (Juhwangmi, Sinhwangmi) types depending on the first principal component (PC1, 68%). Therefore, it was found that the texture types of SP cultivars could be predicted from hardness of cooked root and are in relation to AIS and starch contents, and peak viscosity of raw powder.

Influence of sugarcane bagasse variability on sugar recovery for cellulosic ethanol production

In the context of cellulosic ethanol production, special attention must be given to the raw material, as it affects final product yield. As observed for sugarcane, bagasse variations may derive from several elements, for instance edaphoclimatic factors, seasonality, maturation stage and harvesting techniques. Therefore, in the present work, to investigate the impact of raw material characteristics on process performance, sugarcane bagasse from four harvests from October/2010 to October/2011 was pretreated by steam explosion and had its soluble and insoluble solids contents measured, following enzymatic hydrolysis to assess glucan conversion. As confirmed by ANOVA, glucose concentration was related to the solids content in the reactor, whereas glucan conversion was related to the enzymatic load. Variations in raw material composition were indeed observed to significantly interfere in the final sugar recovery, probably due to the increase in the impurities observed as a result of the type of harvest performed in 2011.

Rheometry of coarse biomass at high temperature and pressure

We designed, constructed, and tested a new device that can measure the rheological properties of lignocellulosic biomass slurries with high solids concentrations (>25%) containing large particles (>10 mm), and that can operate at high temperatures (>230 °C), high pressures (>2.8 MPa), and low pH (<1.0). Rheological properties measured with this Lignocellulosic Biomass Rheometer (LCBR) are consistent with those measured with another instrument. Biomass samples investigated are yield stress materials, consistent with previous reports. For modest temperatures, the viscosity decreases reversibly with increasing temperature. When the biomass is exposed to sufficiently high temperature and low pH, we observe an irreversible decrease in apparent viscosity, consistent with that expected as hydrolysis reactions reduce the concentration of insoluble solids.

Cactus pear peel snacks prepared by instant pressure drop texturing: Effect of process variables on bioactive compounds and functional properties

Cactus pear (Opuntia ficus-indica) has a growing interest from both food manufacturers and consumers due to its medicinal and functional traits. Peel is a major waste from cactus pear juice industry accounting for about 38 % of the fruit weight. New concept of snacks preparation has been developed using instant controlled pressure drop (Detente instantanee controlee, DIC) techniques that provide a texturing stage between initial and final hot air drying stages. In this study, the application of DIC of cactus pear peel (CPP) was performed to be used as starch-free snacks with functional attributes. DIC resulted in high crispness CPP snacks with improved structural and nutritional attributes as well as high relative expansion ratio (up to 21 times). DIC expanded CPP snacks exhibited cutting force (3.34 N) that was much lower than untreated CPP (19.41 N). It is worth noting that optimized DIC treatment (P = 0.6 MPa for t = 15 s) allowed more availability of phenolic compounds and β-carotene by 83 and 551 %, respectively. In addition, antioxidant activity was increased up to 53 %. Results showed that steam pressure had significant effect on fat and alcohol insoluble solids (AIS) contents, wherein the correlation coefficients revealed critical relationships between structural and biochemical availabilities. Therefore, DIC could be used as an innovative technology to value this by-product leading to manufacture of crispy CPP snacks with high nutritious quality. There was a significant difference among the DIC treated and untreated CPP in respect to sensory properties, DIC treated CPP at operation conditions of saturated steam pressure = 0.6 MPa and processing time = 15 had the highest acceptability.

석장(간장소금)의 이화학적 특성

Seok-jang is one of traditional seasonings prepared by solidification of the mixture of say sauce and salt for long period of aging time. In this study, the physiochemical properties of Seok-jang were investigated for the substitution of solar salt. Seok-jang exhibited highest mineral (P, Na, Fe, Mn, and Al) contents than those of solar salt and soy sauce, while showed lower soluble solids content than that of soy sauce. Seok-jang also exerted the highest pH value 7.70 compared to solar salt and soy sauce. Whereas magnesium and calcium contents of solar salts were 2.90 and 0.26 ppm, which were significantly higher than those of Seok-jang. In color values, L* value was highest in solar salt and lowest in say sauce, While the highest a* and b* value were 6.19 and 18.2 observed in Seok-jang followed by a solar salt and soy sauce. On the other hand, less amount of insoluble solid and sand powder content were 0.03 and 0.07% found in Seok-jang, respectively. In conclusion, Seok-jang was suitable for the potentional substitution of natural salt ingredient.

Influence of Particle Size and Concentration on Rheological Behaviour of Reconstituted Apple Purees

This work investigates the impact of structural parameters on the rheological behaviour of apple purees. Reconstructed apple purees from 0 g/100 g up to 2.32 g/100 g of insoluble solids content and varying in particle size were prepared. Three different particle size distributions were obtained by mechanical treatment only, to modify both size and morphology of the particles without modifying the intrinsic rigidity of the cell walls. Rheological measurements showed that the insoluble solids content have a first order effect on the rheological behaviour of the suspensions: three concentrations domains were observed in both dynamic and flow measurements. A model is proposed for each domain. The existence of a weak network between particles is clearly shown over a critical concentration of insoluble solids (cell walls) depending on particle size distribution (semi-diluted domain). In a concentrated domain, particles are on close packing conditions and their apparent volume begin to shrink. Particle size and shape also play an important role on the rheological behaviour of reconstructed apple puree. Due to their irregular shape, cell clusters clog the medium at lower concentration compared to individual cells.

Improved methods for the determination of drying conditions and fraction insoluble solids (FIS) in biomass pretreatment slurry

Accurate and precise chemical characterization of biomass feedstocks and process intermediates is a requirement for successful technical and economic evaluation of biofuel conversion technologies. The uncertainty in primary measurements of the fraction insoluble solid (FIS) content of dilute acid pretreated corn stover slurry is the major contributor to uncertainty in yield calculations for enzymatic hydrolysis of cellulose to glucose. This uncertainty is propagated through process models and impacts modeled fuel costs. The challenge in measuring FIS is obtaining an accurate measurement of insoluble matter in the pretreated materials, while appropriately accounting for all biomass derived components. Three methods were tested to improve this measurement. One used physical separation of liquid and solid phases, and two utilized direct determination of dry matter content in two fractions. We offer a comparison of drying methods. Our results show utilizing a microwave dryer to directly determine dry matter content is the optimal method for determining FIS, based on the low time requirements and the method optimization done using model slurries.

Strategies to achieve high-solids enzymatic hydrolysis of dilute-acid pretreated corn stover

Three strategies were presented to achieve high solids loading while maximizing carbohydrate conversion, which are fed-batch, splitting/thickening, and clarifier processes. Enzymatic hydrolysis was performed at water insoluble solids (WIS) of 15% using washed dilute-acid pretreated corn stover. The carbohydrate concentration increased from 31.8 to 99.3g/L when the insoluble solids content increased from 5% to 15% WIS, while the final carbohydrate conversion was decreased from 78.4% to 73.2%. For the fed-batch process, a carbohydrate conversion efficiency of 76.8% was achieved when solid was split into 60:20:20 ratio, with all enzymes added first. For the splitting/thickening process, a carbohydrate conversion of 76.5% was realized when the filtrate was recycled to simulate a steady-state process. Lastly, the clarifier process was evaluated and the highest carbohydrate conversion of 81.4% was achieved. All of these results suggests the possibility of enzymatic hydrolysis at high solids to make the overall conversion cost-competitive.

Rheological and some physicochemical characteristics of selected floral honeys from plants of caatinga

The aim of this paper was to investigate the physicochemical characteristics and rheological behavior of some floral honeys from species of wild plants found in the Caatinga biome, as well as, correlate honey viscosities with its chemical composition. Thus, five honeys with floral predominance of typical plants foraged by honeybees in Caatinga were analyzed. Results showed that moisture content of honeys ranged from 17.45 to 21.50 g/100g. The samples exhibited higher fructose content (37.58 - 43.95 g/100g) and lower glucose content (27.41- 33.80 g/100g). The glucose-water ratio ranged from 1.55 to 1.80. Sucrose contents, excluding Croton campestris honey sample, exhibited values above the highest sucrose content (6.0 g/100g) allowed by Brazilian norm. The ash content ranged from 0.02 to 0.19 %. The insoluble solids content were above 0.1 g/100 g. The electrical conductivity ranged between 144.90 and 412.55 µS.cm-1. All the honey samples behaved as Newtonian fluids. The viscosity values, measured at 293 K, varied from 1.90 to 8.55 Pa.s. An empirical mathematical model adapted from the Arrhenius model provides a good description of honey viscosity as a function of combined effects of temperature and moisture content.

Combined substrate, enzyme and yeast feed in simultaneous saccharification and fermentation allow bioethanol production from pretreated spruce biomass at high solids loadings

BackgroundEconomically feasible cellulosic ethanol production requires that the process can be operated at high solid loadings, which currently imparts technical challenges including inefficient mixing leading to heat and mass transfer limitations and high concentrations of inhibitory compounds hindering microbial activity during simultaneous saccharification and fermentation (SSF) process. Consequently, there is a need to develop cost effective processes overcoming the challenges when working at high solid loadings.ResultsIn this study we have modified the yeast cultivation procedure and designed a SSF process to address some of the challenges at high water insoluble solids (WIS) content. The slurry of non-detoxified pretreated spruce when used in a batch SSF at 19% (w/w) WIS was found to be inhibitory to Saccharomyces cerevisiae Thermosacc that produced 2 g l-1 of ethanol. In order to reduce the inhibitory effect, the non-washed solid fraction containing reduced amount of inhibitors compared to the slurry was used in the SSF. Further, the cells were cultivated in the liquid fraction of pretreated spruce in a continuous culture wherein the outflow of cell suspension was used as cell feed to the SSF reactor in order to maintain the metabolic state of the cell. Enhanced cell viability was observed with cell, enzyme and substrate feed in a SSF producing 40 g l-1 ethanol after 96 h corresponding to 53% of theoretical yield based on available hexose sugars compared to 28 g l-1 ethanol in SSF with enzyme and substrate feed but no cell feed resulting in 37% of theoretical yield at a high solids loading of 20% (w/w) WIS content. The fed-batch SSF also significantly eased the mixing, which is usually challenging in batch SSF at high solids loading.ConclusionsA simple modification of the cell cultivation procedure together with a combination of yeast, enzyme and substrate feed in a fed-batch SSF process, made it possible to operate at high solids loadings in a conventional bioreactor. The proposed process strategy significantly increased the yeast cell viability and overall ethanol yield. It was also possible to obtain 4% (w/v) ethanol concentration, which is a minimum requirement for an economical distillation process.