Optimal Conditions For Production Research Articles

Turning fish canning wastewater into resources: Effluents and operational conditions selection for volatile fatty acids production

The potential of three fish canning wastewaters to produce volatile fatty acids (VFA) was evaluated using a stepwise procedure at laboratory scale. Batch tests (0.5 L), at different food to microorganism ratios (F/M), presented tuna and mussel cooking wastewaters as the highest yield substrates (60 % and 80 %, respectively). F/M ratios tested did not significantly influence the yield or the VFA spectrum. Continuous reactors (5 L) were operated with these two wastewaters at different hydraulic retention times (HRT). The shortest HRT studied (2 d) favoured the yield and the production of longer-chain VFA (butyric and valeric acids) in tuna wastewater. However, for mussel wastewater, the yield decreased 2-fold and the production of short-chain VFA (acetic acid) was favoured. This study offers an overview of the best fish canning wastewater, from a point of view of maximum VFA yield, and its optimal operational conditions for VFA production.

Evaluation of Chemical and Physical Triggers for Enhanced Photosynthetic Glycerol Production in Different Dunaliella Isolates

The salt-tolerant marine microalgae Dunaliella tertiolecta is reported to generate significant amounts of intracellular glycerol as an osmoprotectant under high salt conditions. This study highlights the phylogenetic distribution and comparative glycerol biosynthesis of seven new Dunaliella isolates compared to a D. tertiolecta reference strain. Phylogenetic analysis indicates that all Dunaliella isolates are newly discovered and do not relate to the D. tertiolecta reference. Several studies have identified light color and intensity and salt concentration alone as the most inducing factors impacting glycerol productivity. This study aims to optimize glycerol production by investigating these described factors singularly and in combination to improve the glycerol product titer. Glycerol production data indicate that cultivation with white light of an intensity between 500 and 2000 μmol m−2 s−1 as opposed to 100 μmol m−2 s−1 achieves higher biomass and thereby higher glycerol titers for all our tested Dunaliella strains. Moreover, applying higher light intensity in a cultivation of 1.5 M NaCl and an increase to 3 M NaCl resulted in hyperosmotic stress conditions, providing the highest glycerol titer. Under these optimal light intensity and salt conditions, the glycerol titer of D. tertiolecta could be doubled to 0.79 mg mL−1 in comparison to 100 μmol m−2 s−1 and salt stress to 2 M NaCl, and was higher compared to singularly optimized conditions. Furthermore, under the same conditions, glycerol extracts from new Dunaliella isolates did provide up to 0.94 mg mL−1. This highly pure algae-glycerol obtained under optimal production conditions can find widespread applications, e.g., in the pharmaceutical industry or the production of sustainable carbon fibers.

Innovative Solution for Invasive Species and Water Pollution: Hydrochar Synthesis from Pleco Fish Biomass

In recent years, the invasive pleco fish has emerged as a global concern due to its adverse effects on ecosystems and economic activities, particularly in various water bodies in Mexico. This study introduces an innovative solution, employing microwave-assisted hydrothermal carbonization (MHTC) to synthesize hydrochar from pleco fish biomass. The research aimed to optimize synthesis conditions to enhance hydrochar yield, calorific value, and adsorption capacities for fluoride and cadmium in water. MHTC, characterized by low energy consumption, high reaction rates, and a simple design, was employed as a thermochemical process for hydrochar production. Key findings revealed that through response surface analysis, the study identified the optimal synthesis conditions for hydrochar production, maximizing yield and adsorption capacities while minimizing energy consumption. Physicochemical characterization demonstrated that hydrochars derived from pleco fish biomass exhibited mesoporous structures with fragmented surfaces, resembling hydroxyapatite, a major component of bone. Hydrochars derived from pleco fish biomass exhibited promising adsorption capacities for fluoride and cadmium in water, with hydrochar from Exp. 1 (90 min, 160 °C) showing the highest adsorption capacity for fluoride (4.16 mg/g), while Exp. 5 (90 min, 180 °C) demonstrated superior adsorption capacity for cadmium (98.5 mg/g). Furthermore, the utilization of pleco fish biomass for hydrochar production not only offers an eco-friendly disposal method for invasive species but also addresses fluoride and cadmium contamination issues, contributing to sustainable waste management and water treatment solutions. The resulting hydrochar, rich in solid fuel content with low pollutant emissions, presents a promising approach for waste management and carbon sequestration. Moreover, the optimized synthesis conditions pave the way for sustainable applications in energy production, addressing critical environmental and public health concerns. This research provides valuable insights into the potential of microwave-assisted hydrothermal carbonization for transforming invasive species into valuable resources, thereby mitigating environmental challenges and promoting sustainable development.

Effects of biogas slurry on hydrothermal carbonization of digestate: Synergistic valorization of hydrochars and aqueous phase

In this study, livestock manure digestate (LMD) was used as feedstock for hydrothermal carbonization (HTC) at different temperature (180–260 °C) and residence time (0–4 h). Nutrient flow and distribution during the HTC process were evaluated by comparing the effects of livestock manure biogas slurry (LBS) and ultrapure water (UW) to determine the optimal reaction conditions for the synergistic production and application of hydrochars (HC) and aqueous phases (AP). Compared with UW, the HC yields derived from LBS as solvent were increased by 27.05–38.24% under the same conditions. The C content, high heating value (HHV), and energy densification of HC obtained from LMD and UW were higher than those obtained from LMD and LBS, and the ash content was lower. While, LBS circumstance improved the porosity, N content and some trace elements e.g. Ca, Fe and Mg in HC that showed excellent fertility potential. In addition, the recovery rate of K, TOC, NH4+-N, and TN concentrations in AP were significantly higher in the LBS circumstance than in UW. The results show that the addition of UW is more favorable for fuel generation, and the HC obtained from LMD and UW at 220 °C has the potential to be used as a fuel. Whereas, the addition of LBS enhanced the potential of HC and AP for agricultural applications simultaneously. It is recommended to use HC and AP obtained from LMD and LBS at 240 °C for using as fertilizer.

Optimizing Methylene Blue Dye Adsorption onto Liquid Natural Rubber-Based Hydrogel: Kinetics, Isotherms and Reusability

In recent years, notable advancements have taken place in the textile industry, particularly with the widespread use of synthetic dyes such as methylene blue (MB). However, the environmental impact of these dyes has raised significant concerns. Their potential to influence both chemical and biochemical demand poses risks, leading to potential disruptions in aquatic plant photosynthesis. Additionally, concerns exist regarding the toxicity and potential carcinogenicity of these dyes to humans. This study achieved successful hydrogel synthesis through the efficient utilization of ultrasonic methods, combining liquid natural rubber (LNR), acrylic acid (AAc), and pectin (Pc) to adsorb MB from aqueous solutions. Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) were employed to analyze the structure. Utilizing Response Surface Methodology (RSM), the study investigated the effects of the AAc:LNR weight ratio and Pc weight on hydrogel preparation for MB removal. This led to the development of a quadratic polynomial model with an ANOVA-derived R2 value of 0.9970. Optimal conditions for hydrogel production were identified as a 3.00 g/g AAc:LNR weight ratio and 0.0325g of Pc, resulting in an impressive 99.07% MB removal effectiveness. The limit of detection (LOD) for methylene blue adsorption was calculated at 0.64 ppm. The kinetics and isotherms of MB removal were described by the pseudo-second-order and Freundlich models, respectively. Furthermore, the investigation into hydrogel reusability demonstrated its capability for up to five utilization cycles. The LNR/AAc/Pc hydrogel exhibits promising potential as an effective, cost-efficient, and environmentally conscious adsorbent for MB removal. This makes it applicable to water treatment scenarios involving cationic dyes.

Application and study on preparation of bio-asphalt by modified phenolic resin from corn straw tar

XPS, GPC, FT-IR, and GC–MS analyses were conducted on corn straw tar and 70# petroleum asphalt. The results indicate that the sulfur content in corn straw tar is lower than that in petroleum asphalt, potentially mitigating the volatilization of harmful substances upon substituting petroleum asphalt. This finding serves as evidence for the substantial presence of phenolic substances in corn straw tar. Upon employing the BOX-Behnken response surface analysis and utilizing resin yield as the evaluation index, the significance of three factors was established as follows: reaction time > phenol molar ratio > straw tar content. Based on the secondary multiple regression model, the optimal conditions for synthetic resin production are a phenolic mole ratio of 0.8, a reaction time of 125 min, and a straw tar dosage of 10 %. An assessment of resin viscosity at different VI temperatures reveals that corn stover tar can partially replace phenol and formaldehyde in the condensation reaction. Additionally, viscosity improvement is observed at elevated temperatures. Thermal gravimetric(TG) spectroscopy indicates lower mass loss in B-PF resin at high temperatures compared to PF resin or corn stover tar. In the evaluation of biological bitumen performance, it is discerned that the mixing amount of the prepared biological bitumen should be controlled at approximately 10 % of its performance. This ensures optimal efficacy without adversely affecting the performance of petroleum bitumen.

Machine learning assisted improved desalination pilot system design and experimentation for the circular economy

Desalination is among the most feasible solutions to supply sustainable and clean drinking water in water scarcity areas. In this regard, Multi-Effect Desalination (MED) systems are particularly preferred for harsh feeds (high temperature and salinity) because of their robust mode of operation for water production. However, maintaining the efficient operation of the MED systems is challenging because of the large system design and variables' interdependencies that are sensitive to the distillate production. Therefore, this research leverages the power of machine learning and optimization to estimate the optimal operating conditions for the maximum distillate production from the MED system. In the first step, detailed experimentation is conducted for distillate production against hot water temperature (HWT) varying from 38 to 70 °C, and feed water temperature (FWT) is changed from 34 to 42 °C. Whereas, the feed flow rate (FFR) is investigated to be varied nearly from 3.6 to 8.7 LPM in the three stages, i.e., FFR-S1, FFR-S2 and FFR-S3. The compiled dataset is used to make the process models of the MED system by three ML-based algorithms, i.e., Artificial Neural Network (ANN), Support Vector Machine (SVM), and Gaussian Process Regression (GPR) under rigorous hyperparameters optimization. GPR exhibited superior predictive performance than those of ANN and SVM on R2 value of 0.99 and RMSE of 0.026 LPM. Monte Carlo technique-based variable significance analysis revealed that the HWT has the highest effect on distillate production with a percentage significance of 95.6 %. Then Genetic Algorithm is used to maximize the distillate production with the GPR model embedded in the optimization problem. The GPR-GA driven maximum distillate production is estimated on HWT = 70 ± 0.5 °C, FWT = 40 ± 2.5 °C, FFR-S1 = 6 ± 2.6 LPM, FFR-S2 = 7 ± 1 LPM and FFR-S3 = 7 ± 1. The ML-GA-based system analysis and optimization of the MED system can boost the distillate production that promotes operation excellence and circular economy from the desalination sector.

Transdisciplinary Tactics and Prospects for Medical and Commercial Advancement in Kefir

Background: Kefir, a fermented milk beverage with a rich cultural heritage, has garnered significant attention due to its health benefits and commercial potential. This study explores the convergence of medical science, technology, and market dynamics to position kefir as a functional food with therapeutic applications. Objective: The study aimed to evaluate the health benefits of kefir, optimize its production processes, and investigate its therapeutic potential in chronic diseases and injuries. Methods: A randomized controlled trial was conducted with participants divided into kefir and control groups. Pre- and post-intervention health assessments were performed, measuring cardiovascular health, blood sugar levels, immune response markers, and neurological function. Biochemical analyses of blood samples were conducted to identify changes due to kefir consumption. Statistical analyses were performed using SPSS version 25. For process optimization, Response Surface Methodology (RSM) was applied to optimize fermentation conditions. Experimental studies included in vitro cell culture experiments and in vivo animal models to assess kefir’s effects on diabetes, Alzheimer's disease, and cancer. Microbial analysis was performed using genomic and proteomic techniques, and consumer sensory evaluations were conducted for new kefir formulations. Results: The kefir group showed a significant reduction in mean blood sugar levels from 96.62 mg/dL to 85.18 mg/dL (t-statistic=5.16, p=0.000004), while the control group showed no significant change. Optimized production conditions were determined to be a temperature of 25°C, fermentation time of 24 hours, and a grain-to-milk ratio of 0.1, achieving a quality score of 500. In the diabetes model, the kefir-treated group had a significant reduction in HbA1c levels (6.75) compared to the control group (7.41) (t-statistic=6.14, p=8.12×10^-8). For Alzheimer's disease, amyloid plaque deposition decreased significantly in the kefir group (37.34) versus the control group (50.13) (t-statistic=5.70, p=4.29×10^-7). In the cancer model, tumor growth was significantly reduced in the kefir group (64.18) compared to the control group (98.10) (t-statistic=7.45, p=5.09×10^-10). Microbial counts were highest and most stable under Condition A (11.05×10^7, SD=6.33×10^5). Consumer sensory evaluations of soymilk-based kefir resulted in a mean score of 3.1 (SD=1.32). Conclusion: Kefir demonstrates significant health benefits, including blood sugar regulation, and therapeutic potential in managing diabetes, Alzheimer's disease, and cancer. Optimized production conditions enhance its commercial viability. Future research should focus on long-term effects and real-world applications to validate these findings.

Effects of Selective Laser Melting Process Parameters on Structural, Mechanical, Tribological and Corrosion Properties of CoCrFeMnNi High Entropy Alloy

AbstractThe structural, tribological, mechanical, corrosion, and other properties of materials produced by laser-based powder bed fusion additive manufacturing methods are significantly affected by production parameters and strategies. Therefore, understanding and controlling the effects of the parameters used in the manufacturing process on the material properties is extremely important for determining optimum production conditions and for saving time and materials. This study aimed to determine the optimal laser parameter values for CoCrFeMnNi high-entropy alloy powders using the selective laser melting (SLM) method. The layer thickness was kept constant during experimentation. 5 different laser powers and 10 varying laser scanning speeds were tested, with hatch spacing from 30 to 90%. After determining the optimal laser parameters for SLM, prismatic samples were fabricated in different build orientations (0°, 45°, and 90°), and subsequently, their structural, mechanical, tribological, and corrosion properties were compared. Melt pool morphology could not be obtained at 20—40 and 60W laser powers and at all laser scanning speeds used at these laser powers. At 100 W laser power, 600 mm/s laser scanning speed, and 70% hatch spacing parameters, an ultimate tensile stress of 550 MPa and elongation of 48% were obtained. Among the samples produced in different build orientations, the sample produced with a 0° build orientation exhibited the highest relative density (99.94%), the highest microhardness (201.2 HV0.1), the lowest friction coefficient (0.7025), and the lowest wear and corrosion rates (0.7875 mpy). Additionally, SLM parameters were evaluated to have a significant impact on the performance of all properties of the samples. Graphical Abstract

Production, characterization and application of polygalacturonase produced by Lentinus tigrinus CCMB 553

Polygalacturonases can be used to improve the processing of fruit juices and wines. This study aimed to produce, characterize and evaluate the potential application of polygalacturonase obtained from Lentinus tigrinus CCMB 553 in mango juice clarification. The fungal was isolated from the northeastern semi-arid region and fermented using Passiflora cincinnata bark as a substrate for solid state fermentation. The optimal conditions for enzyme production were obtained by applying the three-level factorial experimental design and were defined as 9 days and 30 °C for time and temperature, respectively. The optimal pH and temperature were determined by applying the Doehlert design and the results showed higher production between 45 and 60 °C and 4.0 and 5.5 for temperature and pH respectively. Km and Vmax of polygalacturonase from Lentinus tigrinus were 2.7 mg/mL and 12.86 μmol/min. The enzyme maintained 40 % residual activity after 30 min at 80 C. The influence of cations on enzyme activity was studied, and calcium ions seem to have a positive influence on enzyme activity, while Fe2+ ions have a negative influence. K+, Na+ and NH4+ salts showed little influence on the polygalacturonase activity of Lentinus tigrinus. The application in the clarification of mango juice (Mangifera indica) using optimal conditions obtained resulted in a reduction of 45% of the viscosity and the clarification by about 79%. The results show that the polygalacturonase produced by Lentinus tigrinus CCMB 553 was efficiently applied in mango juice, improving the quality of the juice.

Production and quality evaluation of a novel γ-aminobutyric acid-enriched yogurt.

γ-aminobutyric acid (GABA) is a neurotransmitter inhibitor that has beneficial effects on various health conditions such as hypertension, cognitive dysfunction, and anxiety. In this study, we investigated a novel yogurt naturally enriched with GABA using a Levilactobacillus brevis strain isolated in our laboratory; the specific optimum yogurt production conditions for this strain were determined. We isolated an L. brevis strain and used it to produce yogurt naturally enriched with GABA. We explored the optimal conditions to enhance GABA yield, including fermentation temperature, inoculation amount, L-monosodium glutamate (L-MSG) concentration, fermentation time, and sucrose content. We also performed mixed fermentation with Streptococcus thermophilus and evaluated the quality of the yogurt. Following optimization (43°C, 8% inoculation amount, 1.5 g/L L-MSG, and 8% sucrose for 40 h of fermentation), the GABA yield of the yogurt increased by 2.2 times, reaching 75.3 mg/100 g. Mixed fermentation with S. thermophilus demonstrated favorable results, achieving a GABA yield akin to that found in some commercially available functional foods. Moreover, the viable microbe count in the GABA-enriched yogurt exceeded 1 × 108 cfu/mL, which is higher than that of commercial standards. The yogurt also exhibited a suitable water-holding capacity, viscosity, 3-week storage time, and favorable sensory test results. This study highlights the potential of naturally enriched GABA yogurt as a competitive commercial yogurt with beneficial health effects.

Preparation and characterization of composite-modified PA6 fiber for spectral heating and heat storage applications

Abstract Composite coating technology was used to prepare a modified polyamide 6 (PA6) polymer material masterbatch with low mutual interference and good spinnability using molybdenum oxide, tungsten trioxide, graphene oxide, etc., as modifiers. Experiment shows that using nanoscale composite-coated modified masterbatches capable of spectral heating and heat storage in the preparation of nylon 6 fiber, adding modified masterbatches with a mass ratio of 6% online, and controlling various process parameters can result in good functionality and usability as well as enable consistent production. Optimal production conditions are achieved by utilizing pre-dried PA6 chips with a moisture content of 420 ppm. The master batch is subjected to drying at a temperature of 95°C for 12 h. During this process, the master batch is introduced at an addition ratio of 6%. Subsequent spinning is conducted at a speed of 4,300 m·min−1 and a temperature of 255°C. Cooling is facilitated by air set at a temperature of 17°C, flowing at a speed of 0.45 m·min−1. In the production line, one roller operates without heating, while the second roller is maintained at a temperature range of 160°C. The stretching process is performed at a ratio of 1.3. To ensure proper lubrication, an oil rate of 1.3% is applied. These meticulously controlled process parameters collectively contribute to the most favorable production status.

Optimization of Enzymatic Transesterification of Acid Oil for Biodiesel Production Using a Low-Cost Lipase: The Effect of Transesterification Conditions and the Synergy of Lipases with Different Regioselectivity.

This study describes the enzymatic production of second-generation biodiesel using low-quality acid oil as a substrate. Biolipasa-R, a commercially available and low-cost lipase, was employed for enzymatic transesterification. Response surface methodology was applied to optimize the enzymatic transesterification process. The optimal conditions for biodiesel production, which comprised 42% lipase concentration (per weight of oil), 32% water content (per weight of oil), a methanol to oil molar ratio of 3:1, pH 7.0 and reaction temperature 30°C, resulted in the highest fatty acid methyl ester (FAME) content (71.3%). Subsequently, the synergistic effect of two lipases with different regioselectivities under the optimum transesterification conditions was studied, aiming at the enhancement of process efficiency. The transesterification efficiency of immobilized Biolipasa-R was determined and compared to that of Biolipasa-R in its free form. The results revealed a good performance on FAME content (66.5%), while the recycling of immobilized lipase resulted in a decrease in transesterification efficiency after three consecutive uses.

Evaluation of environmental parameters for optimal cell density, biomass, lipid, and biodiesel production in scenedesmus: Focus on suspension and biofilm methods

The study focused on investigating the impact of various environmental parameters on the production of Scenedesmus, a unicellular alga known for its industrial and food value. The parameters studied included production method, temperature, lighting period, light intensity, and pH, with a particular emphasis on suspension and biofilm production methods. The results highlighted optimal conditions for different aspects of production, such as cell density, biomass production, lipid production, and biodiesel production. Specifically, the findings indicated that the highest cell density was achieved at a temperature of 25 °C, light intensity of 3000 lux, lighting period of 16 h, and pH of 8. For biomass production, the optimal conditions were a temperature of 25 °C, light intensity of 3000 lux, lighting period of 18 h, and pH of 9. The greatest lipid production was observed at a temperature of 20 °C, light intensity of 4000 lux, lighting period of 18 h, and pH of 8. Moreover, the highest biodiesel production was recorded at a temperature of 25 °C, light intensity of 3000 lux, lighting period of 18 h, and pH of 8. Notably, the study found that the biofilm production method outperformed the suspension method across various parameters, including cell density, biomass production, lipid production, and biodiesel production. These results contribute to the existing knowledge of optimal conditions for microalgae production and underscore the potential of Scenedesmus in industrial and food applications.

Multiomics study on co-fermentation of chemically enhanced sludge and waste activated sludge to produce volatile fatty acids under different temperatures and pHs

This study examined the effects of different temperatures (37°C and 45°C) and pH (uncontrolled, 8 and 10) on the co-fermentation of FeCl3, anionic polyacrylamide (a-PAM) settling chemical enhanced primary sedimentation (CEPS), and waste activated sludge (WAS) to produce volatile fatty acids (VFAs), which analyzed through characterization, microbial community, and untargeted metabolic pathways. Further, to investigate the interacting effects, temperatures of 37°C, 45°C, and pHs of 8 and 10 were chosen, with a sludge ratio of 7.5. The hydrolysis of sludge was aided by the concentration of soluble chemical oxygen demand (SCOD) rising as temperature and pH rose. Nevertheless, elevated SCOD concentrations failed to materialize into benefits for acid production. Therefore, considering practical applications, the optimal conditions for acid production were determined to be 37°C and pH 10, with a concentration of 3411.17 ± 119.92 mg COD/L. A thorough investigation of correlations between microbial communities, differential metabolites, and environmental factors was carried out, highlighting the significance of pH in relation to microbial and acid production performance. That instance, the pH affects acid generation efficiency more so than temperature parameters. Within the microbial community, there is a considerable positive correlation between several distinct metabolites and Steptococcus, Trichococcus, and Tepidimimicrobium. These metabolites are intimately associated with the materials and energy needed for biological cell production and metabolism. This could be as a result of how environmental influences alter the distribution of microbial populations, which influences various metabolites and ultimately the process of producing acid.

Effectiveness study of recrystallisation method in pharmaceutical salt production from processed salt with zero waste concept

Indonesia's vast archipelago offers abundant seawater resources, holding the potential for salt production. Salt, a vital commodity in human life, typically contains sodium chloride and impurities like Ca2+, Mg2+, SO42−, and K+. Pharmaceutical salt is an industrial category adhering to pharmacopoeial standards regarding sodium chloride levels and impurity content, ensuring quality for drug preparations in Indonesia. Prior research indicates that recrystallisation, specifically evaporation crystallisation, enhances salt quality by increasing NaCl content. Chemical precipitating agents like NaOH and Na2CO3 can be introduced to improve salt purity further. This study aims to identify optimal conditions for pharmaceutical salt production from processed salt raw materials, considering crystallisation time, stirring speed, chemical additives (NaOH and Na2CO3), and double crystallisation stages. The method commences with pre-treatment, involving salt dissolution in distilled water to saturation, with the addition of precipitating agents as per designated variables. Precipitates formed from precipitating agents (NaOH and Na2CO3) are isolated through filtration. The filtrate undergoes evaporation crystallisation at 103 °C, varying between single and double crystallisation. Salt crystals are separated, dried, and weighed to calculate yield. Pharmaceutical salt is analysed for water content, NaCl, and impurities (Ca2+, Mg2+, SO42−, and K+). The optimal conditions for pharmaceutical salt production were double crystallisation with a 20 % excess of chemicals (NaOH and Na2CO3), 100 min of crystallisation time, and a stirring speed of 600 rpm. This yielded a 15 % NaCl content of 99.87 %, Mg2+ at 0 ppm, Ca2+ at 69.6 ppm, SO42− at 366 ppm, K+ at 370 ppm, and water content at 0.166 %. Notably, the pharmaceutical salt production process generates no waste, as byproducts like Mg(OH)2 and CaCO3 can be recycled and hold commercial value. However, it is essential to re-evaluate raw materials and technologies to address the market's high cost and competitiveness issues.

INHIBIION ACTIVITY OF SOME PLANT SEEDS EXTRACTS AGAINST THE PROTEASE PRODUCED FROM LOCAL ISOLATE OF CANDIDA ALBICANS ISOLATE USING SOLID STATE FERMENTATION

This study was aimed at inhibition of purified protease produced by C. albicans using plant seeds extract. One hundred two local C. albicans isolates that were isolated and identified by microscopic and biochemical tests were submitted to primary and secondary screening techniques in order to select the qualified C. albicans isolate for protease synthesis. Among these isolates, nineteen isolates with the highest hydrolysis zone on skim milk media (primary screening) were chosen for secondary screening. It has been found that C. albicansV56 had the highest productivity of the enzyme (41.8U/mg protein). The optimum conditions of protease production by selected isolate using solid state fermentation by using wheat bran as best substrate , temperature 28 °C and pH 7, after 5 days of incubation . The enzyme was purified by concentration with sucrose, then used gel filtration chromatography using Sephadex G-75. The results show two peaks. The first peak has a purification folds 6.5 time with an enzyme yield of 13.08 %, while peak 2 has a purification folds 3.3 time with an enzyme yield of 20%. The purified enzyme exhibited maximal activity at pH 6.0 for peak 1 and 3.0 for peak 2, whereas the maximum stability was 7.0 for peak 1 and 8 for peak 2. The optimal temperature for purified enzyme activity was 40 for peak 1 and 30 for peak 2, and it was stable until 45°C. Protease activity was inhibited with local plant seed extracts. Lathyrus sativus extract inhibits approximately 50 % of protease activity.

The Value of Indigenous <i>Saccharomyces cerevisiae</i> Strains as Useful Enzymes Producers: A Systematic Review

This systematic review has focused on the selection and characterization of indigenous Saccharomyces cerevisiae strains for enzymes' production obtained from the fermentation process. The primary studies assessed have demonstrated that indigenous S. cerevisiae strains produce a wide range of enzymes during fermentation. These strains have shown different characteristics and were isolated from various locations, including those belonging to the main components of the wine production chain. The research methodology applied to find primary studies about the optimal conditions for enzyme production was effective and identified a wide range of enzyme classes. Cultivation media amended with natural or synthetic inducer substrates were found to be suitable carbon and/or nitrogen sources for producing enzymes of interest in plate-based screening. In submerged fermentation studies, the use of agro-industrial residues has been identified as a relevant carbon source for microbe development and metabolism. For the indigenous S. cerevisiae strains, the majority of the enzymes found belong to the glucosidases and hydrolases classes. Due to the activity of these enzymes, yeasts have been traditionally used in classic biotechnological applications, particularly in the process of alcoholic fermentations. Those enzymes are responsible for producing metabolites (such as aromatic compounds) that contribute to the desirable aroma and/or taste during the fermentation of wine, as well as other fermented or distilled beverages. The methods used for enzyme screening were of quantitative and/or qualitative nature and were carried out under acidic pH conditions (3.5-6.5) and at temperatures of 28-35 ℃. The results of this systematic review have shown that the enzymes from indigenous S. cerevisiae are highly relevant in various biotechnological applications, particularly in the food industry. Conclusions and future perspectives of our findings were discussed in terms of potential developments of novel application methods of the indigenous yeasts and their enzymes in agriculture and industry.

Production and Optimization of Extracellular α-amylase From Halophilic Bacteria Cytobacillus oceanisediminis Isolated From Wadi-El-Natrun, Egypt

The current study aimed to maximize α-amylase enzyme production by halophilic bacteria Cytobacillus oceanisediminis isolated from soil of Wadi-El-Natrun, Egypt. The results showed that of 21 halophilic bacterial isolates recovered from saline soil samples, eight isolates were high amylase producers. Interestingly, the bacterial isolate AHB6 exhibited the highest extracellular amylase production and was selected for further studies. This isolate was molecularly identified based on the 16srRNA gene sequencing as Cytobacillus oceanisediminis and has the accession number OM759999. The optimum temperature for α-amylase enzyme was 45 °C and exhibited thermostability at 45 °C for 1 h and retained more than 80% of its original activity. The α-amylase enzyme was active in almost all tested pHs and reached its highest activity at pH 9. Also, the optimum culture conditions for α-amylase enzyme production were wheat bran as carbon source, 2 g/l K2HPO4 as potassium source, 6 g/l MgSO4 as magnesium source and 0.5 g/l KNO3 as nitrogen source. These findings suggest the applicability of bacterial isolate Cytobacillus oceanisediminis as a potent producer of α-amylase for industrial purposes. Keywords: Amylase; Optimization; Cytobacillus oceanisediminis; Starch hydrolysis; Thermo-halophilic bacteria.

Production, purification, and determination of the biochemical properties of β-glucosidase in Trichoderma koningii via solid substrate fermentation.

The β-glucosidase enzyme was obtained from Trichoderma koningii Oudem. NRRL 54330 under optimal conditions by solid substrate fermentation (SSF) using corn cobs as substrate. The enzyme was purified by two-step procedures, ammonium sulphate precipitation and cefarose-4B-l-tyrosine-1-naphthylamine hydrophobic interaction chromatography, followed by biochemical and kinetic characterisation. The β-glucosidase was obtained from T.koningii using ground corn cob as substrate and Na2HPO4, pH 9, as humidification medium. The optimum conditions for enzyme production by SSF were 30 °C and 6days. The purification efficiency of the obtained β-glucosidase was calculated to be 22.56-fold with a yield of 73.51 %. In the determination of β-glucosidase activity, p-nitrophenyl-β-d-glucopyranoside (pNPG) substrate was used, and the optimum pH and temperature values at which β-glucosidase showed high activity were determined to be pH 3.0 and 75 °C. The purity of the enzyme and the presence/number of subunits were checked using two different electrophoretic methods, SDS-PAGE and NATIVE-PAGE electrophoretic methods. The K m and V max values of the purified enzyme were determined to be 0.16 mM and 2000 EU respectively. Itwas also found that d-(+)-glucose and δ-gluconolactone inhibitors exhibited competitive inhibition of β-glucosidase in the presence of pNPG.