Initial Sugar Research Articles

Optimization of Citrus Pulp Waste-Based Medium for Improved Bacterial Nanocellulose Production.

Bacterial nanocellulose (BC) has attracted significant attention across a wide array of applications due to its distinctive characteristics. Recently, there has been increasing interest in leveraging waste biomass to improve sustainability in BC biogenesis processes. This study focuses on optimizing the citrus pulp waste (CPW) medium to enhance BC production using Komagataeibacter sucrofermentans. The screening of initial medium pH, yeast extract, CPW sugar and inoculum concentrations was conducted using the Plackett-Burman design, with BC yield (mgDW/gCPW) as the model response. The significant parameters, i.e., CPW sugars and yeast extract concentrations, were optimized using response surface methodology, employing a five-level, two-factor central composite design. The optimized CPW-based growth medium resulted in a final yield of 66.7 ± 5.1 mgDW/gCPW, representing a 14-fold increase compared to non-optimized conditions (4.3 ± 0.4 mgBC/gCPW). Material characterization analysis indicated that the produced BC showed high thermal stability (30% mass retained at 600 °C) and a crystallinity index value of 71%. Additionally, to enhance process sustainability, spent baker's yeast hydrolysate (BYH) was assessed as a substitute for yeast extract, leading to a final BC titer of 9.3 ± 0.6 g/L.

Optimization of Bacterial Cellulose Production from Waste Figs by Komagataeibacter xylinus

This study aimed to use waste figs as an alternative substrate for bacterial cellulose (BC) production by Komagataeibacter xylinus and optimize the identified process parameters to maximize the concentration of BC. Among the nutrients screened by Plackett–Burman (PB) design, yeast extract was found to be significant in BC production. Response surface methodology was used to investigate the effect of fermentation parameters on BC production. A maximum BC concentration of (8.45 g/L), which is among the highest BC concentrations reported so far, was achieved at the optimum levels of fermentation variables (initial pH 6.05, initial sugar concentration 62.75 g/L, temperature 30 °C). The utilization of response surface methodology (RSM) proved valuable in both optimizing and finding the interactions between process variables during BC production. Scanning electron microscope (SEM) analysis showed a dense structure of BC, characterized by ribbon-like nanofibrils with diameters ranging from 23 to 90 nm while the attenuated total reflection–Fourier transform infrared (ATR-FTIR) spectrum of BC confirmed that the material obtained was cellulose. The X-ray diffraction (XRD) analysis showed that the crystallinity of the BC samples was 70% for BC produced on waste fig medium and 61% for BC produced on Hestrin–Schramm (HS) medium. This is the first detailed study on the production of BC from waste figs, and the findings of this study demonstrated that waste figs can be used as an effective substrate for the production of BC.

The Production of Water Kefir Drink with the Addition of Dried Figs in the Horizontal Rotating Tubular Bioreactor.

Water kefir is a product obtained through the fermentation of sucrose solution, usually with some kind of dried fruit addition, by a combined culture of micro-organisms which are contained within kefir grains. Its popularity is rising because of the simplicity of its preparation and its anti-inflammatory, antioxidant, probiotic, and antibacterial effects. In this research, the water kefir production was studied in 250 mL jars, as well as in a horizontal rotating tubular bioreactor (HRTB). The first part of the research was conducted in smaller-scale (jars), wherein the optimal fruit and fruit portions were determined. These experiments included the addition of dried plums, apricots, raisins, dates, cranberries, papaya, and figs into 150 mL of initial sugar solution. Also, the optimal ratio between dried fruit and sucrose solution (0.2) at the beginning of the bioprocess was determined. The second part of this research was conducted using HRTB. The experiments in the HRTB were carried out by using different operational modes (constant or interval bioreactor rotation). A total of six different bioreactor setups were used, and in all experiments, figs were added at the beginning of the bioprocess (0.2 ratio between dried figs and sucrose solution). On the basis of the obtained results, the interval bioreactor rotation mode proved to be the better HRTB mode for the production of the water kefir, as the yield of the main fermentation products was higher, and their ratios were the most adequate for the quality of water kefir drink. The optimal results were obtained via HRTB setup 3/57 (3 min rotation, 57 min pause within 1 h) and rotation speed of 3 rpm. Furthermore, it is clear that HRTB has great potential for water kefir production due to the fact that HRTB experiments showed shorter fermentation times (at least five times) than water kefir production in jars.

Optimizing bioethanol production from sweet sorghum stem juice under very high gravity fermentation and temperature stress conditions

This study optimized ethanol production from sweet sorghum stem juice (SSJ) by Saccharomyces cerevisiae NP01 under very high gravity (VHG) fermentation in 500-mL air–locked flasks at 30 °C. Response surface methodology based on a Box-Behnken design was employed to optimize initial sugar (267 g/L), urea (3.24 g/L), and cell concentration (1.32 × 108cells/mL) for maximization of ethanol concentration (PE), productivity (QP), and sugar consumption (%SC). The experimental values (PE, 119.29 g/L; QP, 2.49 g/L.h and %SC,91.83 %) under optimal conditions were close to the predicted values, verifying the optimization process. Aeration (2.5 vvm for 4 h) increased viable cell counts and decreased glycerol production (a by-product), but not fermentation efficiency. An osmoprotectant (40 mM potassium chloride combined with 10 mM potassium hydroxide, KCl/KOH) at 30 °C had no positive effect on ethanol fermentation efficiency. However, at 25 °C, the osmoprotectant increased PE from 106 to 116 g/L and ethanol yield from 0.46 to 0.49 g/g. At 35–37 °C, it prolonged cell viability, increasing PE by 5–12 g/L and %SC by 3–8 % without affecting ethanol yield. However, at 39 °C, no positive impact occurred on ethanol fermentation efficiency. The findings from this study, particularly the optimized fermentation conditions and stress tolerance strategies, could guide the scale-up to an industrial level of bioethanol production from sweet sorghum stem juice or other feedstocks using VHG fermentation, contributing to the development of more efficient and sustainable biofuel production processes.

Production of ethanol from oil palm trunk by simultaneous saccharification and fermentation process at bench scale

Abstract A largenumber of oil palm trees are replanted every year. Considering the extent of replanting and OPT’s high starch and sugar content, it was determined to be a potential raw material for bioethanol production. This study conducted ethanol production by simultaneous saccharification and fermentation of starch-rich powder extracted from oil palm trunks. Fermentation was conducted on a 100 L bench scale to evaluate the feasibility and further development of the process before the process is implemented at a larger scale. The preparation of the starch-rich flour involves shredding, drying, and screening of the trunks until the starch-rich powder passes through an 80-mesh sieve. Furthermore, starch was liquefied and partially saccharified. Subsequent saccharification was performed simultaneously with fermentation. The initial total sugar content was adjusted to 15 % w/v and starch was enzymatically hydrolyzed using commercial α-amylase (Liquozyme) and glucoamylase (Novozyme) produced by NOVO. Fermentation was performed using Saccharomyces cerevisiae Hakken No. 1. Since the starch-rich flour contains useful nutrients and growth factors for microbes, the fermentation medium only required the addition of a nitrogen source (urea 1 g/L). The ethanol content after fermentation was approximately 8.7 % v/v with a fermentation ratio of 88.8 %. These results were obtained at a fermentation time of 60 h. One OPT yields 80 kg of starch-rich powder, equivalent to 33 liters of bioethanol.

Use of Syzygium aromaticum L. Fermented Plant Extract to Enhance Antioxidant Potential: Fermentation Kinetics

The concept of our research is related to the use of stems from S. aromaticum L. in the fermentation process in order to obtain new cosmetic raw materials with high antioxidant potential that are safe for human fibroblasts (HDFs) and keratinocytes (HaCaTs). This evaluation involves treating cell lines with different concentrations of fermented extracts to establish a noncytotoxic dose range. The focus was on evaluating antioxidant activity (AA), total polyphenol content (TPC), and lactic acid efficiency (LAe). For this purpose, the most favourable technological parameters of the fermentation process of stems were determined, including the type of microorganisms, initial sugar content, plant raw material content, and fermentation time. In the present study, lactic acid was obtained with maximum efficiency by stem fermentation in the presence of lactic acid bacteria (LAB) and molasses as a source of six-carbon sugars. In addition, fermentation kinetics was investigated, the essence of which was to identify the technological parameters that allow the highest values of the main functions describing the process (AA, TPC LAe). Two kinetic models were used to determine the kinetics of process function changes during fermentation. The most favourable fermentation conditions for maximum antioxidant activity (26.88 mmol Tx/L ± 0.19), total polyphenol content (5.96 mmol GA/L ± 0.19), and lactic acid efficiency (88% ± 1) were: type of microorganism L. rhamnosus MI-0272, initial sugar content 3.20%, plant raw material content 6.40%, and a fermentation time of 9 days. The values of chelating activity (ChA), AA, and TPC in the fermented stems increased more than two-fold compared to the non-fermented extracts. Reducing activity (RA) and LAe increased to 46.22 mmol Fe3+/L ± 0.29 and 88% ± 1, respectively. Of the kinetic models adopted, follow-up reaction equations and first-order equations best described the time-dependent changes taking place. This study shows that the process function values of AA and LAe are dependent on the LAB strain and the content of the plant material, and the rate of change of TPC may largely depend on the forms of phenolic compounds formed during fermentation.

Valorization of Cashew Apple Waste into a Low-Alcohol, Healthy Drink Using a Co-Culture of Cyberlindnera rhodanensis DK and Lactobacillus pentosus A14-6.

This study investigated the potential of microbial fermentative transforming processes in valorizing the cashew apple by-product into a low-alcohol, health-benefiting beverage. We particularly investigated the use of a non-Saccharomyces yeast, Cyberlindnera rhodanensis DK, as the main targeted microbe. At 30 °C without agitation, C. rhodanensis DK caused changes in key parameters during the fermentation of cashew apple juice (CAJ) in terms of varied pH values and initial sugar concentrations. This result indicated that pure CAJ, with pH adjusted to 6 and with the original 6.85% (w/v) total sugar content, was the most feasible condition, as glucose and fructose were mostly consumed at 12 days of fermentation. A co-culture approach with either Saccharomyces cerevisiae TISTR 5088 or Lactobacillus pentosus A14-6 was investigated to improve both physicochemical and fermentation characteristics. Co-fermentation with S. cerevisiae TISTR 5088 resulted in significantly increased ethanol accumulation to 33.61 ± 0.11 g/L, but diminished bioactive compounds, antioxidant activity, and antidiabetic potential. In contrast, co-fermentation with L. pentosus A14-6 demonstrated excellent outcomes, as it significantly increased sugar consumption and finally remained at only 4.95 g/L compared to C. rhodanensis DK alone, produced lower levels of ethanol at only 19.47 ± 0.06 g/L, and higher total titratable acid (TTA), resulting in a final pH of 3.6. In addition, co-fermentation with this lactic acid bacterium significantly enhanced bioactive compounds and antioxidant activity and also retained potential antidiabetic properties. These findings highlight the feasibility of using tailored microbial fermentation strategies to produce low-alcohol beverages with enhanced health-promoting properties from CAJ; however, product-development processes following health food regulations and sensory evaluation are necessary.

Optimization of poly(3-hydroxybutyrate) production with simulating corn stover hydrolysates by Paraburkholderia sacchari

In this study, poly(3-hydroxybutyrate) production by Paraburkholderia sacchari was investigated using glucose-xylose mixtures as simulated corn stover hydrolysates to optimize the culture media. Box-Behnken Design (BBD) was selected to comprehensively understand the effects of four variables including sugar concentration, molar C/N ratio, phosphorus concentration, and sugar ratio on P(3HB) production. The optimized parameters were identified as initial sugar concentration (23 g/L), molar C/N ratio (44), phosphorus concentration (8.7 g/L), and sugar ratio (1.9∶1). Under the optimal conditions, P. sacchari achieved the maximum P(3HB) accumulation of 55.8 % with a P(3HB) titer of 5.16 g/L (0.23 g/g Sugar). The extracted polymer was confirmed as P(3HB) and exhibited enhanced thermostability. Furthermore, P(3HB) was successfully synthesized from ball-milled corn stover hydrolysate under optimized conditions with the P(3HB) titer reached 7.66 g/L (0.33 g/g Sugar), which was higher than the pure mixed sugar system and other reports on lignocellulose hydrolysates with batch fermentation (<5 g/L). Therefore, P. sacchari exhibits the potential for P(3HB) production using corn stover hydrolysates as an inexpensive substrate.

Investigation of wine fermentation of three-leaf cayratia (Cayratia trifolia L.) using Saccharomyces cerevisiae 2.1

Background Cayratia trifolia has been extensively studied for its bioactive components and medicinal properties. This study was carried out to evaluate the fermentation ability of Saccharomyces cerevisiae 2.1 yeast to determine suitable fermentation conditions. Methods The initial sugar content for three-leaf cayratia fermentation and fermentation efficiency were calculated. The temperature for three-leaf cayratia fermentation, incubation time, and preliminary 1 liter of three-leaf cayratia wine fermentation were determined. All treatments showed that the total sugar content decreased after 9 days of fermentation compared to the initial level. Temperature during fermentation has a direct effect on yeast activity. Temperature increases the growth of yeast and speed of enzyme activity. The fermentation time changes depending on temperature, initial soluble solid contents, and yeast strains, leading to changes in the ethanol content after the end of fermentation. Results The results showed that the S. cerevisiae 2.1 was able to ferment at room temperature with an initial pH of 4.5, 24 °Brix, and a yeast density of 107 cells/mL. The appropriate fermentation conditions determined for S. cerevisiae 2.1 were 24 °Brix and incubation at room temperature (28-33°C) with a fermentation time of 11 days. Conclusion In 1-L scale fermentation, three-leaf cayratia wine had 9.46% (v/v) and the fermentation efficiency was 90.34%. The wine produced had a unique color, flavor, and aroma that met the sensory evaluation of the Vietnamese national standard TCVN-3217:79.

Study of acid hydrolysis and submerged fermentation parameters in second generation ethanol production using cassava waste

Biofuels are an alternative to reduce the environmental impacts caused by the use of petroleum-based fuels. Second generation ethanol comes from lignocellulosic materials that are little used or discarded in the environment, including agro-industrial waste. These residues are rich in sugars that can be converted by ethanol-producing microorganisms. In this context, the present work uses cassava waste (Manihot esculenta Crantz) obtained during the processing of starch as a raw material for the production of cellulosic ethanol, as well as evaluating different parameters in acid hydrolysis and during submerged fermentation using the strain Saccharomyces cerevisiae ATCC 26602. Experiments of acid hydrolysis of these residues with sulfuric acid in concentrations of 0.5% to 5.0% (v/v) were carried out. The results demonstrated that 2.0% H2SO4 for 10 min. reaction at 121 ºC/1.1 atm in an autoclave reached the highest release of reducing sugars present in the residue (131.09 g.L-1). The ideal conditions for alcoholic fermentation using yeast were pH 6.5, temperature of 35 ºC, without rotation and initial reducing sugar concentration of 50 g.L-1, resulting in 21.23 g.L-1 of ethanol with productivity of 1.86 g.L-¹.h-¹ and theoretical yield of 96.5% after 12 hours of fermentation. The results indicated that the cassava waste serve as a potential substrate for the production of second generation ethanol. Thus, this study provides data on the most suitable conditions for the use of these industrial wastes aiming at the generation of a renewable fuel, an increasingly attractive feature for the world, where the economic and environmental concern is growing.

Seizure occurrences among hypoglycemic patients in the emergency department.

Symptomatic hypoglycemia is a common problem in the emergency department (ED). However, without appropriate recognition and management, hypoglycemia remains a potentially fatal condition. The cause of sudden death associated with hypoglycemia might be attributed to cardiac arrhythmias and hypoxia with seizures. Despite advances in diabetes mellitus management and social background, the frequency and characteristics of patients with hypoglycemia-related seizures have remained unknown. Hence, our study aimed to investigate the frequency and characteristics of patients with hypoglycemia presenting with seizures in the ED. This retrospective observational study was conducted in a single tertiary care center. Patient information was retrieved from the final diagnostic records in the ED. We reviewed all medical records and included patients with symptomatic hypoglycemia aged 16 years or older. The primary outcome was the frequency of seizures in patients with hypoglycemia. We also compared the initial blood sugar levels of the patients with and without seizures. We included a total of 380 patients (median age, 72 years, IQR 64-80 years; median initial blood sugar, 34 mg/dL, IQR 24-46; 62.9% male). Nineteen of 380 patients (5.0%) had seizures. Although 16 of the 19 patients had diabetes mellitus, none of the 19 patients had a history of epilepsy. The initial blood sugar levels of the patients with and without seizures were not significantly different (p = 0.97). Approximately 5% of the patients with hypoglycemia presented with seizures. Blood glucose levels of hypoglycemic patients with and without seizures did not differ.

ANALYSIS OF DIET COMPLIANCE ON CHANGES IN BLOOD SUGAR LEVELS IN THE BODY IN DIABETES MILLITUS PATIENTS

Diabetes is a metabolic disorder characterized by increased blood glucose as a result of impaired insulin production or impaired insulin work or both because until now there is no drug that can treat the disease. The aim of this study was to analyze dietary compliance with changes in blood sugar levels in diabetes mellitus sufferers. This research was conducted using a qualitative descriptive research method. This research was carried out at the Kenten Permai Public Health Center, Palembang. Qualitative data analysis was inductive, then developed into a hypothesis. In this qualitative research, the number of informants was 3 diabetes mellitus patients and 1 expert informant, namely a nutritionist. Based on the research results, it can be concluded that there is one respondent whose diet is compliant, one respondent who is close to compliant and there is a respondent who is not compliant. D is close to adhering to the schedule but not with the quantity and type, the initial blood sugar was 186mg/dl to 160mg/dl. Mrs. R, who complied with the amount and type with her initial clock of 213 mg/dl, became 136 mg/dl. Mrs. R, who was less compliant, experienced a very slight decrease in blood sugar from 328 mg/dl to 298 mg/dl. All respondents knew about the diabetes mellitus diet, and began to apply it in their daily lives.

Nisin as a safe and effective alternative to sulfur dioxide in enhancing dateplum persimmon (Diospyros lotus L.) wine quality

Sulfur dioxide (SO2) is widely used in the fruit wine industry due to its antioxidant and antibacterial properties. However, concerns about its potential harmful effects on human health have prompted researchers to seek alternative treatments. In this study, nisin, a natural nontoxic polypeptide, was introduced as a preservative during dateplum persimmon (Diospyros lotus L.) winemaking. The ideal fermentation conditions were determined through response surface methodology optimization: a nisin content of 0.21 g/L, a yeast concentration of 0.22%, and an initial sugar content of 255 g/L. Enological parameters, microbiological analysis, sensory evaluation, and volatile component information were compared between dateplum persimmon wines made with nisin and those made with SO2 both before and after three months of aging. Notably, the major components were consistent across all the samples, with 3-methylbutanol, ethyl caprylate, 2-methylbutanol, and phenethyl alcohol imparting apple brandy, honey, and rose aromas to the fruit wines. Overall, these results suggest that nisin can serve as an effective and acceptable alternative to SO2, demonstrating satisfactory antibacterial properties without adverse effects on wine quality. This study marks the first exploration of the potential use of nisin in the production of dateplum persimmon wine, offering a promising avenue for the replacement of SO2 in fruit wine processing.

Mathematical modeling as a tool in kombucha beverages bioactive quality control

This study examined the application of mathematical models on total flavonoids content and sensory mark of kombucha beverages on winery effluent. Process parameters were as follows: 0, 3, 6 and 9 days of fermentation time; 20, 25 and 30 ?C of fermentation temperature and 3, 5 and 7% of initial total reducing sugars. Total flavonoids were determined spectrophotometrically and sensory mark by a descriptive test and five points category scale. Total flavonoids content decreased during the applied kombucha fermentation process, which lasted for 9 days. On average, total sensory mark suggested that consume kombucha products are obtained after 3 days of the fermentation, regardless on the fermentation temperature or sugars content. In order to produce kombucha beverage with the highest bioactive quality, response surface methodology proposed the following process parameters: 3 days of fermentation, 7% of initial total sugars and 30?C process temperature.

Influence of main production variables to nutritional characteristics of winery effluent Kombucha

Determination of sugar, nitrogen and phosphorus consumption by kombucha culture is necessary in order to gain additional insight into the kombucha metabolic pathways, nutritional value of the produced beverages, and to set basis for optimising the conditions for large scale production. Kombucha beverage was made using effluent obtained from grape must clarification phase of white wine production. The fermentation medium was prepared by diluting the sterilized initial medium with approximately 16% of total reducing sugars to 3, 5, and 7% of total reducing sugars. The duration of the fermentation was nine days at 20, 25, and 30?C. Sugars, nitrogen and phosphorus content was measured using DNS, Kjeldahl and molybdenum blue method, respectively. The highest sugars content was in the initial medium (16.34%) and the lowest was after nine days of fermentation at 30 ?C with 3% initial sugars content (0.17%). Residual levels of sugars, nitrogen and phosphorus after three days were modelled using response surface methodology. The proposed mathematical models for sugars and nitrogen content showed an exceptional correlation with the experimentally obtained values. With this study the insight into kombucha?s consumption of basic nutrients, nutritional value of the obtained products and optimization of products composition was provided

Efficient Production of Succinic Acid from Sugarcane Bagasse Hydrolysate by Actinobacillus succinogenes GXAS137

Sugarcane bagasse (SCB) is an abundant agricultural waste, rich in cellulose and hemicellulose, that could be used as an ideal raw material for succinic acid (SA) production. A two-step chemical pretreatment, involving alkali extraction and alkaline hydrogen peroxide treatment, was utilized to treat SCB, followed by multi-enzyme hydrolysis to obtain a reducing sugar hydrolysate mainly composed of glucose and xylose. Optimization of the multi-enzyme hydrolysis of pretreated SCB resulted in a final reducing sugar concentration of 78.34 g/L. In order to enhance the bioconversion of SCB to SA and to reduce the production costs, the initial reducing sugar concentration, nitrogen source, and MgCO3 content were further optimized. The results demonstrated that the inexpensive corn steep liquor powder (CSLP) could be utilized as an alternative nitrogen source to yeast extract for the production of SA; and the optimal concentrations of initial reducing sugar, CSLP, and MgCO3 were 70 g/L, 18 g/L, and 60 g/L, respectively. When fed-batch fermentation was conducted in a 2 L stirred bioreactor, approximately 72.9 g/L of SA was produced, with a yield of 83.2% and a productivity of 1.40 g/L/h. The high SA concentration, yield, and productivity achieved in this study demonstrate the potential of SCB, an agricultural waste, as a viable alternative substrate for Actinobacillus succinogenes GXAS137 to produce SA. This lays a solid foundation for the resource utilization of agricultural waste and cost-effective industrial-scale production of SA in the future.

Osmotic Stress Alleviation in Saccharomyces cerevisiae for High Ethanol Fermentations with Different Wort Substrates

High-gravity fermentation, used for ethanol production from sugarcane, corn, and mixed substrates, offers several benefits. Yeast, a rapidly multiplying unicellular microorganism, can be adapted for high sugar and ethanol tolerance on a lab scale. However, different substrates can enhance fermentation efficiency. Our study consisted of two experiments. In the first, we compared simple batch feeding with a fed-batch system for yeast selection in high-gravity fermentation. We ran eight cycles with increasing initial sugar contents (50 to 300 g L−1). No significant differences were observed in the first seven cycles, but in the eighth, the fed-batch system showed lower glycerol and fructose contents and higher cell viability than the simple batch system. In the second experiment, we used the fed-batch system with 300 g L−1 from sugarcane, corn, and mixed wort. The results showed that mixed wort produced higher ethanol contents and greater fermentation efficiency compared to corn and sugarcane as substrates. In conclusion, our findings indicate that the fed-batch system is more suitable for high-gravity fermentation on a lab scale, and the combination of sugarcane juice and corn can enhance fermentation efficiency, paving the way for integrating these substrates in industrial ethanol production.

Bioethanol production from deproteinized cheese whey powder by local strain isolated from soured milk: influence of operating parameters

ABSTRACT In this paper, a local isolated yeast strain was studied for bioethanol production using protein-free cheese whey powder (CWP) in batch alcoholic fermentation experiments. Ethanol tolerance tests were performed with different ethanol concentrations (from 0% to 20%). The maximum ethanol tolerance obtained for our strain was 5% (v/v). The influence of initial lactose concentration, temperature and pH on fermentation kinetic was studied. For initial lactose concentration ranging from 57.5 to 260 gL−1, the highest ethanol production 34.8 gL−1 was obtained at 109 gL−1 initial lactose concentration corresponding to 0.413 gg−1 ethanol yield (YP/S); (While it was noticed less ethanol production, namely 0.178 g g−1) at a higher initial whey sugar concentration of 260 gL−1. The effect of the initial pH on the fermentation was studied at three different values: 3, 4 and 5. The ethanol production reached a maximum of 22 g L−1 with a lactose consumption of 77.62% at pH 4. However, an observed decrease occurred in ethanol production and lactose consumption at pH 3, with values of 10.34 gL-1 and 24.46%, respectively. For the fermentation conducted at the three temperatures of 37°C, 40°C and 43°C, the maximum ethanol production and lactose consumption were 34.82 gL-1 and 80.75%, respectively, achieved at 37°C. The experimental data was analyzed using the Gompertz model to obtain the following kinetic parameters: the maximum ethanol concentration (Pm) was found to be 36.97 gL-1, the maximum ethanol production rate (rp,m) was 0.402 gL−1h−1 and the lag phase (tl) was 10.8 h. The comparison of the isolated Kluyveromyces marxianus TXID4911 strain with the reference strain Kluyveromyces marxianus DSM 5421, showed a relatively close ethanol yield (YP/S) 0.415 and 0.505 gg,−1 respectively.

Enhancing and monitoring spore production in Clostridium butyricum using pH-based regulation strategy and a robust soft sensor based on back-propagation neural networks.

Clostridium butyricumis a probiotic that forms anaerobic spores and plays a crucial role in regulating gut microbiota. However, the total viable cell count and spore yield of C. butyricum in industrial production are comparatively low. To this end, we investigated the metabolic characteristics of the strain and proposed three distinct pH regulation strategies for enhancing spore production. In addition, precise measurement of fermentation parameters such as substrate concentration, total viable cell count, and spore concentration is crucial for successful industrial probiotics production. Nevertheless, online measurement of these intricate parameters in the fermentation of C. butyricum poses a considerable challenge owing to the complex, nonlinear, multivariate, and strongly coupled characteristics of the production process. Therefore, we analyzed the capacitance and conductivity acquired from a viable cell sensor as the core parameters for the fermentation process. Subsequently, a robust soft sensor was developed using a seven-input back-propagation neural network model with input variables of fermentation time, capacitance, conductivity, pH, initial total sugar concentration, ammonium ion concentration, and calcium ion concentration. The model enables the online monitoring of total viable biomass count, substrate concentrations, and spore yield, and can be extended to similar fermentation processes with pH changes as a characteristic feature.

Investigation of wine fermentation of three-leaf cayratia (Cayratia trifolia L.) using Saccharomyces cerevisiae 2.1

Background: Cayratia trifolia has been extensively studied for its bioactive components and medicinal properties. This study was carried out to evaluate the fermentation ability of Saccharomyces cerevisiae 2.1 yeast to determine suitable fermentation conditions. Methods: The initial sugar content for three-leaf cayratia fermentation and fermentation efficiency were calculated. The temperature for three-leaf cayratia fermentation, incubation time, and preliminary 1 liter of three-leaf cayratia wine fermentation were determined. All treatments showed that the total sugar content decreased after 9 days of fermentation compared to the initial level. Temperature during fermentation has a direct effect on yeast activity. Temperature increases the growth of yeast and speed of enzyme activity. The fermentation time changes depending on temperature, initial soluble solid contents, and yeast strains, leading to changes in the ethanol content after the end of fermentation. Results:The results showed that the S. cerevisiae 2.1 strain was able to ferment at room temperature with an initial pH of 4.5, 24 °Brix, and a yeast density of 107 cells/mL. The appropriate fermentation conditions determined for S. cerevisiae 2.1 yeast were 24 °Brix and incubation at room temperature (28-33°C) with a fermentation time of 11 days. Concusion: In 1 liter scale fermentation, three-leaf cayratia wine had 9.46% (v/v) and the fermentation efficiency was 90.34%. The wine produced had a unique color, flavor, and aroma that met the sensory evaluation of the Vietnamese standard TCVN-3217:79.