Optimal Conditions For Production Research Articles

The effect of spent coffee ground (SCG) loading, matrix ratio and biological treatment of SCG on poly(hydroxybutyrate) (PHB)/poly(lactic acid) (PLA) polymer blend

This study investigates the effects of SCG embedded into biodegradable polymer blends and aimed to formulate and characterise biomass-reinforced biocomposites using spent coffee ground (SCG) as reinforcement in PHB/PLA polymer blend. The effect of SCG filler loading and varying PHB/PLA ratios on the tensile properties and morphological characteristics of the biocomposites were examined. The results indicated that tensile properties reduction could be due to its incompatibility with the PHB/PLA matrixSCG aggregation at 40 wt% content resulted in higher void formation compared to lower content at 10 wt%. A PHB/PLA ratio of 50/50 with SCG loading 20 wt% was chosen for biocomposites with treated SCG. Biological treatment of SCG using Phanerochaete chrysosporium CK01 and Aspergillus niger DWA8 indicated P. chrysosporium CK01 necessitated a higher moisture content for optimum growth and enzyme production, whereas the optimal conditions for enzyme production (50–55 %, w/w) differed from those promoting A. niger DWA8 growth (40 %, w/w). SEM micrographs highlighted uniform distribution and effective wetting of treated SCG, resulting in improvements of tensile strength and modulus of biocomposites, respectively. The study demonstrated the effectiveness of sustainable fungal treatment in enhancing the interfacial adhesion between treated SCG and the PHB/PLA matrix.

Molecular identification of protease producer ORSK-4 strain and determination of optimum enzyme production conditions

A microorganism resistant to high temperatures and producing alkaline proteases was isolated from soil samples from a protein-rich region (Kırıkkale/Yahşihan). This isolate, with high protein production, was identified as ORSK-4 by determining its morphological and biochemical properties using the 16s rRNA molecular approach and the Amplified ribosomal DNA restriction analysis (ARDRA) technique employed in strain differentiation. The optimum enzyme production conditions of the strain ORSK-4 were found to be the enzyme media, 3 days of incubation, 27.0 °C, and pH 7.0. Different components were utilized to determine the effect of changing the medium content on enzyme activity. Under the optimal production conditions determined in this way, the enzyme activity of ORSK-4 was found to be higher than that of some ATCC reference Bacillus species. To purify the extracellular protease of ORSK-4, precipitation with ammonium sulfate (30% and 80%), dialysis, and DEAE ion exchange chromatography were performed. SDS-PAGE analysis determined the molecular weight of the purified enzyme as approximately 30 kDa. Although the enzyme showed activity at various pH ranges, it showed its maximum activity when increased up to pH 9.0. In conclusion, the stability of the obtained alkaline protease enzyme under different conditions shows that it can be used in industrial and environmental applications.

Optimized biogas production from poultry manure with respect to pH, C/N, and temperature

This study aims to identify the optimal conditions for generating biogas from poultry manure with respect to pH, C/N ratio, and temperature. The study was conducted in lab batch bioreactor having a working volume of 2 l at different conditions with respect to pH, carbon to nitrogen ratio (C/N), and temperature. A full factorial design is designed to analyze the impact of the three parameters and their interactions. Experiments are replicated four times to ensure the reproducibility of data. Results indicate that temperature is the only influencing parameter on biogas production from poultry manure within a pH range of 6–8 and a C/N ratio range of 10/1 to 40/1. Moreover, there is no interaction between the three parameters, and mesophilic conditions are found to be the optimum conditions for biogas production. The maximum biogas yield of 285 ml/g VS is found in mesophilic conditions at 37 °C with a retention time of 20 days. Biogas production kinetics are similar in mesophilic and thermophilic conditions but vary in psychrophilic conditions.

Production of Conjugated Linoleic Acid (CLA) by Lactiplantibacillus plantarum: A Review with Emphasis on Fermented Foods.

The term Conjugated Linoleic Acid (CLA) refers generically to a class of positional and geometric conjugated dienoic isomers of linoleic acid. Among the isomers of linoleic acid cis9, trans11-CLA (c9, t11-CLA) and trans10, cis12-CLA (t10, c12-CLA) are found to be biologically active isomers, and they occur naturally in milk, dairy products and meat from ruminants. In addition, some vegetables and some seafoods have also been reported to contain CLA. Although the CLA levels in these natural sources are insufficient to confer the essential health benefits, anti-carcinogenic or anti-cancer effects are of current interest. In the rumen, CLA is an intermediate of isomerization and the biohydrogenation process of linoleic acid to stearic acid conducted by ruminal microorganisms. In addition to rumen bacteria, some other bacteria, such as Propionibacterium, Bifidobacterium and some lactic acid bacteria (LAB) are also capable of producing CLA. In this regard, Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) has demonstrated the ability to produce CLA isomers from linoleic acid by multiple enzymatic activities, including hydration, dehydration, and isomerization. L. plantarum is one of the most versatile species of LAB and the bacterium is widely used in the food industry as a microbial food culture. Thus, in this review we critically analyzed the literature produced in the last ten years with the aim to highlight the potentiality as well as the optimal conditions for CLA production by L. plantarum. Evidence was provided suggesting that the use of appropriate strains of L. plantarum, as a starter or additional culture in the production of some fermented foods, can be considered a critical factor in the design of new CLA-enriched functional foods.

Green Macroalgae Hydrolysate for Biofuel Production: Potential of Ulva rigida

In this study, the green macroalgae Ulva rigida, which contains 34.9% carbohydrates, underwent treatment with commercial hydrolytic enzymes. This treatment yielded a hydrolysate that contained 23 ± 0.6 g·L−1 of glucose, which was subsequently fermented with Saccharomyces cerevisiae. The fermentation process resulted in an ethanol concentration of 9.55 ± 0.20 g·L−1. The optimal conditions for ethanol production by S. cerevisiae were identified as follows: non-sterilized conditions, an absence of enrichment, and using an inoculum size of 118 mg·L−1. Under these conditions, the fermentation of the green macroalgal hydrolysate achieved a remarkable conversion efficiency of 80.78%. The ethanol o/t ratio, namely the ratios of the experimental to theoretical ethanol produced, for Scheffersomyces stipitis, Candida guilliermondii, Kluyveromyces marxianus, and S. cerevisiae after 48 h of fermentation were 52.25, 63.20, 70.49, and 82.87%, respectively. Furthermore, S. cerevisiae exhibited the best outcomes in terms of ethanol production (9.35 g·L−1) and conversion efficiency (80.78%) after 24 h (optimal time) of fermentation.

Tailoring ZnO nanorods for efficient photocatalytic production of H2O2 from water without sacrificial agents: A study on length optimization

In this study, we investigated the optimal length of zinc oxide nanorods (ZnO NRs) for the production of photocatalytic hydrogen peroxide (H2O2) using a hydrothermal method at 150 °C with reaction times ranging from 2 to 12 h. The study found that the size of the crystals increased when the reaction duration was extended, resulting in an increase in the size from 26 to 48 nm. SEM measurements indicated that ZnO exhibited longitudinal growth along the c-axis, increasing the nanorod length from 1 μm to 3.5 μm. The bandgaps of the ZnO NRs were between 3.21 and 3.25 eV. The optimal conditions for H2O2 production were identified to be 10 min of sonication and 15 min of UV illumination. The generation of H2O2 increased with the dosage of ZnO, ranging from 0.01 to 0.3 g/20 ml. The highest H2O2 production was attained by employing ZnO NRs at 1.6 μm in length with 49 mgL−1 Under UV irradiation and 28 mgL−1 under sonication irradiation. This study offers new perspectives for the design and production of H2O2 using ZnO NRs of a certain length, which may be beneficial for environmental remediation and energy generation.

Optimization of production conditions, isolation, purification, and characterization of tannase from filamentous fungi.

Tannase-producing filamentous fungi residing alongside tannin-rich ambient in the Northwest Himalayas were isolated at laboratory conditions and further identified by 18S ribosomal RNA gene sequencing. Five most potent tannase producing strains (EI ≥ 2.0), designated Aspergillus fumigatus AN1, Fusarium redolens AN2, Penicillium crustosum AN3, Penicillium restrictum AN4, and Penicillium commune AN5, were characterized. The strain Penicillium crustosum AN3 exhibited a maximum zone dia (25.66mm ± 0.38). During solid-state fermentation, a maximal amount of tannase was attained withPenicillium crustosum AN3 usingpine needles (substrate) by adopting response surface methodology for culture parameter optimization. Gel filtration chromatography yielded 46.48% of the partially purified enzyme with 3.94-fold of tannase purification. We found two subunits in enzyme-117.76 KDa and 88.51 KDa, respectively, in the SDS-PAGE. Furthermore, the characterization of partially purified tannase revealed a maximum enzyme activity of 8.36 U/mL at 30°C using a substrate concentration (methyl gallate) of 10mM. To broaden the knowledge of crude enzyme application, dye degradation studies were subjected to extracellular crude tannase fromPenicillium crustosum AN3 where the maximumdegradation achievedat a low enzyme concentration (5ppm).

Исследование зависимости физико-химических свойств флуоресцентных гибридных полимерных носителей от условий гидротермального синтеза

Currently, the search for new types of carriers for low-molecular weight substances, as well as the development of optimal methods for the effective encapsulation of these substances are important tasks of modern chemistry and pharmacology. However, there are still limitations in this area, among which one of the most significant is the lack of the optimal carrier capable of stably retaining a low-molecular weight substance. The work presents hybrid polymer structures obtained by in situ hydrothermal synthesis as an effective candidate for these purposes. The fluorescent dye rhodamine B has been used as a model low-molecular weight substance for encapsulation into the structures. The resulting hybrid polymer structures demonstrated good stability when stored in an aqueous environment for 336 h with the release of the low-molecular weight dye rhodamine B no more than 2%. In addition, the influence of the conditions for obtaining hybrid carriers (including the composition of the carriers (thickness of the polymer shell and the presence of a calcium carbonate core) and synthesis temperature) on their physical-chemical characteristics has been studied. Thus, the optimal approach for obtaining fluorescent hybrid polymer carriers with a set of desired properties has been revealed. In particular, it has been shown that the optimal production conditions are hydrothermal synthesis temperature of 180 °C and the absence of CaCO 3 core inside the polyelectrolyte shell which allow us to obtain a stable hybrid polymer carrier with bright fluorescence. The results presented in this study can be used to create functional platforms and systems with tunable fluorescent properties and the ability to deliver low-molecular weight substances.

Optimization of Bacterial Cellulose Production by Komagataeibacter rhaeticus K23

The use of bacterial cellulose (BC), having high purity, a high degree of crystallinity, water-holding capacity, tensile strength and adaptability on a broad scale is limited because of the low yield. In this study, the optimal conditions for bio-cellulose production by Komagataeibacter rhaeticus K23 were investigated. Optimal values for temperature, pH, inoculum concentration and incubation time were determined via Taguchi design. The maximum BC production, 9.1 ± 0.66 g·L−1 (dry weight), was obtained from 32 °C, pH 5.5, 8 log CFU·mL−1 and 14 days of incubation. The inoculum concentration was the most significant factor affecting BC yield. A value of 8 log CFU·mL−1 and 14 days of incubation led to significantly higher levels of BC yield than other concentrations (8.5, 9, 9.5, 10 and 10.5 log CFU·mL−1) (p < 0.002) and days (15, 16, 17, 21 and 28) (p < 0.001). The studied features, namely absorption peaks (Fourier transform infrared spectroscopy), pattern and the crystallinity index (X-ray diffraction analysis) of the BC obtained in this study were all in parallel with the characteristics of cellulose I. The study demonstrates that optimized parameters were effective in producing BC with high water-holding capacity, tensile strength, elongation and Young’s modulus (mechanical tests) by K. rhaeticus K23.

Thermocatalytic decomposition of methane to low-carbon hydrogen using LaNi1-xCuxO3 perovskite catalysts

The thermocatalytic decomposition (TCD) of methane is an attractive alternative to produce low-carbon hydrogen and solid carbonaceous materials. In this study, substituted LaNi1-xCuxO3 perovskite catalysts prepared via self-combustion method were investigated for methane TCD. The effect of Ni partial substitution with Cu, varying gas hourly space velocity, temperature and stability on methane conversions were evaluated. PXRD, H2-TPR, SEM-EDS, TGA, and XPS were used to characterize the catalysts. An increase in Cu loading to 50%, increase in temperature and decrease in GHSV resulted in an improvement in methane conversions to 92%. At a GHSV of 2400 ml/gcat.h, no significant deactivation was observed as the stability of the LaNi0.5Cu0.5O3 catalyst increased from 6 to 20 hours’ TOS with methane conversions maintained at 92% where carbon nanofibers were observed on the surface of the spent catalysts. The study demonstrates the potential to prepare LaNi1-xCuxO3 catalysts and identify optimal testing conditions for the novel production of low-carbon hydrogen with minimal catalyst deactivation.

Optimization of Conjugated Linoleic Acid and Eicosapentaenoic Acid Production from Sesame Waste by Response Surface Methodology

Conjugated linoleic acid (CLA) and eicosapentaenoic acid (EPA) have been recognized for their physiological functions and potential as dietary supplements. This study is aimed at investigating the production and enhancing the efficiency of these two acids from Lactiplantibacillus plantarum using sesame waste as a natural, cost-effective, and readily available culture medium. Response surface methodology (RSM) was employed to optimize the production of CLA and EPA in a solid bed system using sesame waste paste as the fermentation substrate. The main processing parameters, including three humidity levels (60%, 70%, and 80%), three inoculum percentages (2%, 4%, and 6% v/v), and three fermentation temperatures (30°C, 37°C, and 44°C), were optimized. An experiment was conducted to validate the determined conditions, and a strong correlation was observed between the experimental results and the predictions made by the software. The optimal conditions for CLA and EPA production were determined to be an inoculation level of 6% with 80% humidity and at 37°C. Gas chromatography analysis of the fermented sesame waste medium revealed that the highest yields of CLAc9t11 and CLAt10c12, as well as eicosapentaenoic acid, were obtained in the medium fermented with 80% humidity and 6% inoculation at 37°C. The respective percentages of these fatty acids in the total fatty acid composition were found to be 0.351% (w/v) and 0.1% (w/v) for CLA and 0.139% (w/v) for EPA under the optimized conditions. These findings contribute to the understanding of CLA and EPA production and highlight the potential of L. plantarum and sesame waste as a fermentation substrate for their efficient production.

Production, characterization and biomedical potential of biosurfactants produced by haloalkaliphilic archaea from Wadi El-Natrun, Egypt

Extreme halophilic archaea that can live in high saline environments can offer potential applications in different biotechnological fields. This study delves into the fascinating field of halophilic archaea and their ability to produce biosurfactants. Some strains of haloarchaea were isolated from Wadi El-Natrun and were screened for biosurfactants production in a standard basal medium using emulsification index assay. Two strains were chosen as the potential strains for surface tension reduction. They were identified as Natrialba sp. BG1 and N3. The biosurfactants production was optimized and the produced emulsifiers were partially purified and identified using FTIR and NMR. Sequential statistical optimization, Plackett–Burman (PB) and Box–Behnken Designs (BBD) were carried out using 5 factors: oil, NaCl, casamino acids, pH, and inoculum size. The most significant factors were used for the next Response Surface Methodology experiment. The final optimal conditions for biosurfactants production were the inoculum size 2% pH 11 and NaCl 250 g/L, for Natrialba sp. BG1 and inoculum size 2.2%, pH 10 and NaCl 100 g/L for Natrialba sp. N3. The produced biosurfactants were tested for wound healing and the results indicated that Natrialba sp. BG1 biosurfactants is more efficient than Natrialba sp. N3 biosurfactants. Biosurfactants extracts were tested for their cytotoxic effects on normal cell line as well as on different cancer cells using MTT assay. The findings demonstrated that varying concentrations of the biosurfactants (31.25, 62.5, 125, 250, 500 and 1000 µg/mL) exhibited cytotoxic effects on the cell lines being tested. Additionally, the outcomes unveiled the presence of anti-inflammatory and antioxidant properties for both biosurfactants. Consequently, they could potentially serve as natural, safe, and efficient novel agents for combating cancer, promoting wound healing, and providing anti-inflammatory and antioxidant benefits.

Production and characterization of rhamnolipids by Pseudomonas aeruginosa isolated in the Amazon region, and potential antiviral, antitumor, and antimicrobial activity

Biosurfactants encompass structurally and chemically diverse molecules with surface active properties, and a broad industrial deployment, including pharmaceuticals. The interest is growing mainly for the low toxicity, biodegradability, and production from renewable sources. In this work, the optimized biosurfactant production by Pseudomonas aeruginosa BM02, isolated from the soil of a mining area in the Brazilian Amazon region was assessed, in addition to its antiviral, antitumor, and antimicrobial activities. The optimal conditions for biosurfactant production were determined using a factorial design, which showed the best yield (2.28 mg/mL) at 25 °C, pH 5, and 1% glycerol. The biosurfactant obtained was characterized as a mixture of rhamnolipids with virucidal properties against Herpes Simplex Virus, Coronavirus, and Respiratory Syncytial Virus, in addition to antimicrobial properties against Gram-positive bacteria (Staphylococcus aureus and Enterococcus faecium), at 50 µg/mL. The antitumor activity of BS (12.5 µg/mL) was also demonstrated, with potential selectivity in reducing the proliferation of breast tumor cells, after 1 min of exposure. These results demonstrate the importance of studying the interconnection between cultivation conditions and properties of industrially important compounds, such as rhamnolipid-type biosurfactant from P. aeruginosa BM02, a promising and sustainable alternative in the development of new antiviral, antitumor, and antimicrobial prototypes.

Immunomodulation Evidence of Nanostructured Recombinant Proteins in Salmonid Cells.

Recent studies have demonstrated that immune-related recombinant proteins can enhance immune function, increasing host survival against infectious diseases in salmonids. This research evaluated inclusion bodies (IBs) of antimicrobial peptides (CAMPIB and HAMPIB) and a cytokine (IL1βIB and TNFαIB) as potential immunostimulants in farmed salmonids. For this purpose, we produced five IBs (including iRFPIB as a control), and we evaluated their ability to modulate immune marker gene expression of three IBs in the RTS11 cell line by RT-qPCR. Additionally, we characterized the scale-up of IBs production by comparing two different scale systems. The results showed that CAMPIB can increase the upregulation of tnfα, il1β, il8, and il10, HAMPIB significantly increases the upregulation of tnfα, inos, and il10, and IL1βIB significantly upregulated the expression of tnfα, il1β, and cox2. A comparison of IL1βIB production showed that the yield was greater in shake flasks than in bioreactors (39 ± 1.15 mg/L and 14.5 ± 4.08 mg/L), and larger nanoparticles were produced in shake flasks (540 ± 129 nm and 427 ± 134 nm, p < 0.0001, respectively). However, compared with its shake flask counterpart, the IL1βIB produced in a bioreactor has an increased immunomodulatory ability. Further studies are needed to understand the immune response pathways activated by IBs and the optimal production conditions in bioreactors, such as a defined medium, fed-batch production, and mechanical bacterial lysis, to increase yield.

Development of a Low-Density Waste-Based Geopolymer Construction Material

The construction industry, integral to national infrastructure development, faces environmental challenges attributed to Portland cement’s high energy consumption and carbon dioxide emissions during production. To address this challenge, this study integrated waste fly ash and polystyrene into geopolymers to enhance environmental sustainability and economic feasibility. The objectives included developing low-density geopolymers using polystyrene inclusion, optimizing component mixing ratios, assessing activator concentration effects, determining the optimal curing conditions, and characterizing the resulting geopolymers. Through experimental investigation, low-density geopolymers were developed with optimized component ratios and curing conditions. The experimental procedure began with the classification of fly ash to determine its suitability for various applications, revealing it to be type F. Geopolymers were fabricated using a mixture of fly ash, water, sodium hydroxide activator, and polystyrene. Varied concentrations of sodium hydroxide and polystyrene were employed. Two curing temperatures, 60 °C and 100 °C, were explored. The results showed that greater sodium hydroxide concentrations improved the structure and compressive strength of the geopolymers. The results also demonstrated a significant correlation between the curing conditions and the mechanical properties of the produced geopolymers. The goal of reducing the density of the geopolymers for lightweight thermal-resistant applications was achieved through polystyrene incorporation. However, polystyrene incorporation negatively impacted the compressive strength. The optimum production conditions for the sodium hydroxide-varied samples were 8 g sodium hydroxide/g sample cured at 100 °C, while the optimum production conditions for polystyrene-varied samples were 1 g polystyrene/g sample cured at 60 °C. The findings confirmed the viability of utilizing fly ash and polystyrene wastes to produce sustainable, low-density, thermal-resistant construction materials. Overall, increasing activator concentration enhances the strength and durability of geopolymers, while polystyrene contributes to the development of lightweight geopolymers, provided the appropriate amount is utilized. To ensure replicability, the formulation procedure and input quantities must be tailored according to the intended geopolymer application. These insights offer practical guidance for optimizing geopolymer manufacturing processes towards enhanced sustainability and performance.

Manufacturing Biodiesel from Cooking Oil Teaching Factory Products Using Bentonite Catalyst with Non-Alcohol Route Method

This research investigates an eco-friendly approach to biodiesel production through non-alcoholic pathways using heterogeneous catalysts. The study examines various ratios of methyl acetate to cooking oil and temperatures, revealing that the optimal conditions for biodiesel production are a 1:4 ratio, utilizing a bentonite catalyst (0.75 g), operating at 60°C for 120 minutes. Fourier Transform Infrared Spectroscopy (FTIR) analysis confirms the presence of ester groups, the primary component of biodiesel. Most biodiesel characteristics align with quality standards, including density (0.8844 kg/m3), cetane number (61.9), and acid number. However, the biodiesel flash point falls below the minimum standard, suggesting a potential area for improvement. This research underscores the potential of using methyl acetate as a heterogeneous catalyst for biodiesel production, with most biodiesel characteristics meeting established quality standards, although further work may be needed to address the flash point issue.

The Effect of Callus Age on Biomass and Flavonoid Production in Talinum paniculatum In Vitro Culture

Talinum paniculatum (Javanese Ginseng) is an herbaceous plant belonging to Talinaceae family that has been known as an important medicinal plant. Flavonoid is one of the prominent bioactive compounds that are contained in all parts of T. paniculatum and has been known for its several bioactivities, including antioxidant, anti-inflammatory, antimicrobial, antidiabetic, and anti-cancer. Callus culture can be used to ensure the quantity and quality of flavonoid production. Callus age is one of the important factors that needs to be considered in order to produce optimum biomass and flavonoid production. Therefore, this research aimed to investigate the effect of callus age on biomass and flavonoid production in T. panicultaum in vitro culture. Young leaves were used as an explant, and callus induction was performed using MS solid media supplemented with kinetin 3 mg/L and 2.4-D 2 mg/L. Biomass and flavonoid production were observed during 0, 28, 35, 42, and 49 days. Results showed that biomass and flavonoid production were influenced by callus age. The production of flavonoid in T. paniculatum callus culture was not linear with the growth of callus (biomass), and the optimum flavonoid production resulted in the 28th days of callus age (49.100 mg QE/g), while the optimum biomass resulted in the 49th days of callus age (4.295 g). It can be concluded that the optimum conditions for biomass and flavonoid production in T. paniculatum callus culture are influenced by different callus ages

Optimization of methane yield from co-digestion of alkalipretreated groundnut shells and duck waste using response surface methodology

Anaerobic co-digestion of lignocellulose feedstock with livestock waste can assist in overcoming the challenges of digesting lignocellulose and balancing the nutrient contents of the process. This study investigated the optimum conditions for methane yield production from anaerobic co-digestion of alkali-pretreated groundnut shells and duck waste using Response Surface Methodology (RSM). A central composite design of the RSM model with three input variables of retention time, temperature, and substrate mixing ratio was used to set up the anaerobic digestion process. Individual and interactive influence of the three process parameters were examined. The result showed that all three process parameters considered are significant and determine the methane yield. The developed RSM model predicted a daily methane yield of 53.33 mL CH4/g VSadded for optimal conditions of 11 days, 26 °C temperature, and 50: 50 mixing ratio, which is not the same as the optimum methane yield observed from the experiment (54.26 mL CH4/g VSadded) and at different process conditions. Cumulative methane yields of 666.72 and 666.66 mL CH4/g VSadded were predicted and observed, respectively, which shows a very close range. The RSM coefficient of determination (R2) value of 0.8251 (82.51%) was observed, indicating a close fit between the predicted and observed yields. Analysis of variance (ANOVA) p < 0.0001 indicates that the developed model could be helpful in anaerobic co-digestion of lignocellulose materials and livestock waste. This study can be replicated at the industrial scale.

Low-temperature culture enhances production of flavivirus virus-like particles in mammalian cells

Flavivirus virus-like particles (VLPs) exhibit a striking structural resemblance to viral particles, making them highly adaptable for various applications, including vaccines and diagnostics. Consequently, increasing VLPs production is important and can be achieved by optimizing expression plasmids and cell culture conditions. While attempting to express genotype III (GIII) Japanese encephalitis virus (JEV) VLPs containing the G104H mutation in the envelope (E) protein, we failed to generate VLPs in COS-1 cells. However, VLPs production was restored by cultivating plasmid-transfected cells at a lower temperature, specifically 28 °C. Furthermore, we observed that the enhancement in JEV VLPs production was independent of amino acid mutations in the E protein. The optimal condition for JEV VLPs production in plasmid-transfected COS-1 cells consisted of an initial culture at 37 °C for 6 h, followed by a shift to 28 °C (37/28 °C) for cultivation. Under 37/28 °C cultivation conditions, flavivirus VLPs production significantly increased in various mammalian cell lines regardless of whether its expression was transiently transfected or clonally selected cells. Remarkably, clonally selected cell lines expressing flavivirus VLPs consistently achieved yields exceeding 1 μg/ml. Binding affinity analyses using monoclonal antibodies revealed similar binding patterns for VLPs of genotype I (GI) JEV, GIII JEV, West Nile virus (WNV), and dengue virus serotype 2 (DENV-2) produced under both 37 °C or 37/28 °C cultivation conditions. In summary, our study demonstrated that the production of flavivirus VLPs can be significantly improved under 37/28 °C cultivation conditions without affecting the conformational structure of the E protein.Keypoints• Low-temperature culture (37/28 °C) enhances production of flavivirus VLPs.• Flavivirus VLPs consistently achieved yields exceeding 1 μg/ml.• 37/28 °C cultivation did not alter the structure of flavivirus VLPs.

An Optimal Culture Medium for Laccase Production and Sugar Cane Vinasse Biotreatment with Trametes villosa Using Plackett-Burman and Central Composite Designs

The optimal conditions for laccase production and vinasse biotreatment with a native strain of Trametes villosa were determined by a screening-optimization approach. Eleven factors including nutrient concentration, vinasse dilution (%v/v), inoculum volume, carbon to nitrogen ratio and initial pH, were investigated for their effects on laccase activity applying the Plackett-Burman screening design. The selected factors were optimized using a central composite design, and then evaluated on a vinasse biotreatment experiment. The factors that contributed the most to the enzymatic activity were the concentrations of MgSO4∙7H2O (A), FeSO4∙7H2O (B) and CuSO4∙5H2O (C), alongside initial pH. After 10 days, laccase activity was 544.038 U L-1 for the following concentrations of A, B and C: 0.250 g L-1, 0.020 mg L-1, and 0.100 g L-1, respectively. Vinasse biotreatment under optimized conditions resulted in 82.74%, 78% and 75.97% of phenol, color, and COD removal respectively, while final pH value was 6.90. These results showed that the native strain of T. villosa has a good potential for further research on laccase production and vinasse sustainable management.