Optimal Conditions For Production Research Articles

Development of a Mammalian Cell Line for Stable Production of Anti-PD-1

Background/Objectives: Immune checkpoint blockade, particularly targeting the programmed cell death 1 (PD-1) receptor, is a promising strategy in cancer immunotherapy. The interaction between PD-1 and its ligands, PD-L1 and PD-L2, is crucial in immune evasion by tumors. Blocking this interaction with monoclonal antibodies like Nivolumab can restore anti-tumor immunity. This study aims to develop a stable expression system for Nivolumab-based anti-PD-1 in the Chinese Hamster Ovary (CHO) DG44 cell line using two different expression vector systems with various signal sequences. Methods: The heavy chain (HC) and light chain (LC) of Nivolumab were cloned into two expression vectors, pOptiVEC and pcDNA3.3. Each vector was engineered with two distinct signal sequences, resulting in the creation of eight recombinant plasmids. These plasmids were co-transfected into CHO DG44 cells in different combinations, allowing for the assessment of stable antibody production. Results: Both pOptiVEC and pcDNA3.3 vectors were successful in stably integrating and expressing the Nivolumab-based anti-PD-1 antibody in CHO DG44 cells. This study found that the choice of signal sequence significantly influenced the quantity of antibodies produced. The optimization of production conditions further enhanced antibody yield, indicating the potential for large-scale production. Conclusions: This study demonstrates that both pOptiVEC and pcDNA3.3 expression systems are effective for the stable production of Nivolumab-based anti-PD-1 in CHO DG44 cells. Signal sequences play a critical role in determining the expression levels, and optimizing production conditions can further increase antibody yield, supporting future applications in cancer immunotherapy.

Novel Micrococcus unila to Produce Glucosamine by Solid-state Fermentation of Shrimp Shell Waste

This study aimed to assess glucosamine production through enzymatic activity, utilizing actinomycetes sourced from shrimp shell waste (SSW) in a solid-state fermentation (SSF) process. A total of 16 actinomycetes underwent chitinase activity screening, and the strain exhibiting the highest chitinolytic index was chosen for subsequent morphological and phylogenetic analyses. High Performance Liquid Chromatography (HPLC) was employed to analyze glucosamine produced from the bioconversion of SSW via SSF. Optimal conditions for glucosamine production were determined by varying time, pH, and temperature. Isolate 18D36-A2 showed the highest chitinolytic index of 1.02 in the 32-mm clean zone. Phylogenetic analysis revealed 97% similarity to the genus Micrococcus, identifying it as a novel Micrococcus unila strain 18D36-A2 and deposited in GenBank. This isolate effectively converted shrimp shells. The findings showcase the bioconversion of SSW to glucosamine through SSF using the Micrococcus unila 18D36-A2. Furthermore, this study establishes a foundation for future research on environmentally friendly and sustainable designs for glucosamine production.

Effect of Growth Conditions on Hemolysin Production from Clinical Isolates of <i>Escherichia Coli</i>

Background: Escherichia coli belongs to the Enterobacteriaceae family and is found in the digestive systems of humans and various animals as normal flora. Objective: This study aims to identify the optimal conditions necessary for the synthesis of hemolysin by E. coli isolated from a variety of clinical contexts. Methods: A total of 120 specimens were collected from different clinical sources in Baghdad Hospitals. Screening for hemolysin production was done by plate and Spectrophotometric methods. Furthermore, many conditions for producing hemolysin from clinical E. coli isolates were investigated including temperature, pH, incubation time, inoculum size, culture medium, and aeration. Results: Six isolates of E. coli exhibited hemolysin production. Optimal conditions for hemolysin production were determined: the temperature was 37 °C with an optical density of 0.931, the pH was 7 with an optical density of 0.976, the incubation period was 24 hours with an optical density of 0.885, 1% inoculum resulting in an optical density of 0.558, brain heart infusion as the best medium with an optical density of 1.697, and a shaker method showing superior results (optical density of 1.235) compared to static aeration (optical density of 0.988). Conclusions: This study identified the optimal conditions necessary for the synthesis of hemolysin by E. coli. By understanding these optimal conditions, researchers may be better equipped to develop strategies for managing and controlling the spread of these pathogenic bacteria.

Electro-activation for efficient lactulose production: The impact of operational parameters, electrolyte types, and environmental conditions

The electro-activation (EA) process has been employed to convert lactose into lactulose, a potent prebiotic with numerous health benefits. The study identified optimal conditions for lactulose production, including a specific current density, the use of calcium chloride as an efficient electrolyte, and the superiority of a steel cathode over a graphite cathode. The formation of intermediates other than lactulose increased as the temperature increased. The changes in pH and oxidation-reduction potential during the isomerization process were observed, highlighting their vital role in the formation of an ideal alkaline environment for lactulose production. The resultant solution produced by the EA process has significant antioxidant characteristics, likely due to the formation of Maillard Reaction Products during lactulose production. In conclusion, the EA system, with optimal operating conditions, is an energy-efficient, reagent-free, and environmentally friendly alternative for lactulose production.

Optimization of diformylfuran production from 5-hydroxymethylfurfural via catalytic oxidation in a packed-bed continuous flow reactor.

DFF's diverse applications in pharmaceuticals, fungicides, and polymer synthesis motivate the development of efficient production methods. This study reports the continuous-flow synthesis of DFF from 5-HMF in a packed-bed reactor. The Box-Behnken design coupled with response surface methodology (RSM) was employed to optimize the reaction parameters (catalyst, solvent, temperature, oxygen flow rate, catalyst amount) for DFF yield. Ru/Al2O3 in toluene proved to be the most effective catalyst-solvent combination. The optimal conditions for DFF production were identified as: 140 °C reaction temperature, 10 ml min-1 oxygen flow rate, and 0.15 g catalyst loading. Under these conditions, a DFF yield of 84.2% was achieved.

Co-cultivation of microalgae and bacteria for optimal bioenergy feedstock production in wastewater by using response surface methodology

This work uses response surface methodology (RSM) to study the co-cultivation of symbiotic indigenous wastewater microalgae and bacteria under different conditions (inoculum ratio of bacteria to microalgae, CO2, light intensity, and harvest time) for optimal bioenergy feedstock production. The findings of this study demonstrate that the symbiotic microalgae-bacteria culture not only increases total microalgal biomass and lipid productivity, but also enlarges microalgal cell size and stimulates lipid accumulation. Meanwhile, inoculum ratio of bacteria to microalgae, light intensity, CO2, and harvest time significantly affect biomass and lipid productivity. CO2 concentration and harvest time have significant interactive effect on lipid productivity. The response of microalgal biomass and lipid productivity varies significantly from 2.1 × 105 to 1.9 × 107 cells/mL and 2.8 × 102 to 3.7 × 1012 Total Fluorescent Units/mL respectively. Conditions for optimum biomass and oil accumulation are 100% of inoculation ratio (bacteria/microalgae), 3.6% of CO2 (v/v), 205.8 µmol/m2/s of light intensity, and 10.6 days of harvest time. This work provides a systematic methodology with RSM to explore the benefits of symbiotic microalgae-bacteria culture, and to optimize various cultivation parameters within complex wastewater environments for practical applications of integrated wastewater-microalgae systems for cost-efficient bioenergy production.

Production and characterization of bioemulsifier from local isolate of Saccharomyces cerevisiae strain JZT351: Antioxidant and antimicrobial effects

AbstractThe widespread use and circulation of industrial emulsifiers pose significant health risks, compounded by their limited availability and high cost. Consequently, there is growing interest in exploring the potential of natural sources, such as microorganisms like yeast, for emulsifier production. In this study, 25 strains of Saccharomyces cerevisiae were isolated from 17 distinct local sources. The yeasts were characterized based on cell shape, size, and colony morphology using yeast malt agar, followed by morphological, microscopic, and biochemical analyzes. Among the isolates, AC1 from a vinegar starter demonstrated superior bioemulsifier production. Emulsification efficiency tests revealed that AC1 exhibited values of 7.1 cm, 0.71 nm, and 34.50%, outperforming other isolates. The biomass yield was approximately 4.35 g/L. This strain was registered in the gene bank as JZT351 (OR115510) after a 100% match with S. cerevisiae. Optimal bioemulsifier production conditions for JZT351 were identified using a liquid yeast extract peptone dextrose medium, with date juice replacing 75% of the glucose, at pH 5.5, 30°C, and 72 h. The resulting emulsification activity, index, and oil displacement were 8.69 cm, 0.95 nm, and 39.7%, respectively. Fourier‐transform infrared spectroscopy (FTIR) compared the functional groups of the bioemulsifier with those of conventional emulsifiers. Molecular characterization was confirmed by 1H NMR. FTIR spectra revealed bioemulsifier bands at 3443.28, 2929.34, 1656.559, 1534.09, 807.06, and 1656.55 cm−1. At 0.5–5 ppm, signals and spectral frequencies corresponded to a mannoprotein structure. The bioemulsifier exhibited 58.09% antioxidant activity at 10 mg/mL, as assessed by DPPH scavenging. It showed the highest inhibition against Pseudomonas aeruginosa and the least against Candida albicans.

Advanced Bioconversion of sugary wastewater: Integrated polyhydroxybutyrate and hydrogen productions in a continuous airlift two-chamber bioreactor

This study utilized a novel Continuous Airlift Two-chamber Bioreactor (CATBR) for the co-production of hydrogen and polyhydroxybutyrate (PHB) from mixed microbial cultures in sugary wastewater. Hydrogen generation was investigated in a defined bacterial consortium that contained mainly Clostridium species, and diverse microbial communities were studied in relation to PHB production, demonstrating the ability of diverse microbial communities to form stable microbial consortia. The impact of hydraulic retention time (HRT), pH, and air flow rate on PHB production was evaluated with special emphasis on volatile suspended solids (VSS).Optimal conditions for hydrogen and PHB production were established at a pH of 5.5, an aeration rate of 1500 mL/h, and an HRT of two days. Hydrogen yield was determined to be 3.14 ± 0.92 mL/g COD, and PHB yield was 31.32% (g PHB/g VSS). Production rates for hydrogen and PHB peaked at 0.23 ± 0.07 L/L.d and 0.64 g PHB/L.d, respectively, with a COD removal efficiency of 85 ± 0.67%. At an HRT of two days, the PHB generation rate was found to be 6–10 times higher than previously reported rates. The application of immobilized cell technology effectively prevented bacterial washout from the reactor, thereby ensuring stable operational conditions.

Eco-friendly production of biodiesel from Carthamus tinctorius L. seeds using bismuth oxide nanocatalysts derived from Cannabis sativa L. Leaf extract

Global challenges in environmental protection, social welfare, and economic growth necessitate increased energy production and related services. Biofuel production from waste biomass presents a promising solution, given its widespread availability. This study focuses on converting highly potent Carthamus tinctorius L. seed oil (51 % w/w) into sustainable biofuel using a novel, highly reactive, recyclable, and eco-friendly bismuth oxide (Bi2O3) nano-catalyst derived from Cannabis sativa L. leaf extract. The physio-chemical properties of the synthesized biodiesel were analyzed using Gas Chromatography/Mass Spectroscopy (GC-MS), Nuclear Magnetic Resonance (NMR), and Fourier-Transform Infrared Spectroscopy (FTIR). Additionally, the green Bi2O3 nanoparticles were characterized through Scanning Electron Microscopy (SEM), Energy Diffraction X-Ray (EDX), and X-Ray Diffraction (XRD). Optimal conditions for biodiesel production were determined using Response Surface Methodology (RSM) in combination with Central Composite Design (CCD), focusing on molar ratio, catalyst loading, and reaction duration. The highest output (94 %) of C. tinctorius-derived biodiesel (CTBD) was achieved under the following conditions: a temperature (75 °C) for time duration (100 min), a methanol to oil ratio (6:1), and a catalyst loading (0.69 wt%). The resulting biodiesel met international standards, with a sulphur content of 0.00097 wt%, and an acid value of (0.34 mg KOH/g). This study demonstrates that converting C. tinctorius waste seed oil into clean bioenergy is an effective waste management strategy that minimizes environmental impact.

Probiotic Encapsulation: Bead Design Improves Bacterial Performance during In Vitro Digestion (Part 2: Operational Conditions of Vibrational Technology).

The development of functional foods is a viable alternative for the prevention of numerous diseases. However, the food industry faces significant challenges in producing functional foods based on probiotics due to their high sensitivity to various processing and gastrointestinal tract conditions. This study aimed to evaluate the effect of the operational conditions during the extrusion encapsulation process using vibrating technology on the viability of Lactobacillus fermentum K73, a lactic acid bacterium with hypocholesterolemia probiotic potential. An optimal experimental design approach was employed to produce sweet whey-sodium alginate (SW-SA) beads with high bacterial content and good morphological characteristics. In this study, the effects of frequency, voltage, and pumping rate were optimized for a 300 μm nozzle. The microspheres were characterized using RAMAN spectroscopy, scanning electron microscopy, and confocal laser scanning microscopy. The optimal conditions for bead production were found: 70 Hz, 250 V, and 20 mL/min with a final cell count of 8.43 Log10 (CFU/mL). The mean particle diameter was 620 ± 5.3 µm, and the experimental encapsulation yield was 94.3 ± 0.8%. The INFOGEST model was used to evaluate the survival of probiotic beads under gastrointestinal tract conditions. Upon exposure to in vitro conditions of oral, gastric, and intestinal phases, the encapsulated viability of L. fermentum was 7.6 Log10 (CFU/mL) using the optimal encapsulation parameters, which significantly improved the survival of probiotic bacteria during both the encapsulation process and under gastrointestinal conditions compared to free cells.

Performance of photocatalytic water splitting for hydrogen production using kelp as a sacrificial agent

The study investigated the influence of catalyst concentration, co-catalyst loading ratio, sacrificial agent concentration, irradiation time, irradiation intensity and different pretreatments of sacrificial agent on hydrogen production, using multistage porous Pd/TiO2 as the catalyst and kelp as the sacrificial agent. The morphological and structural changes in the catalyst, sacrificial agent, and their mixtures before and after the photocatalysis were analyzed using Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and ultraviolet–visible (UV–vis) spectroscopy. Based upon single-factor experiments, it was confirmed that mannitol was the primary substance acting as a sacrificial agent in kelp. Orthogonal experiments were conducted to determine the optimum conditions for hydrogen production with a reaction liquid volume of 100 mL. The highest hydrogen production efficiency was achieved for the following conditions: kelp sacrificial agent's concentration of 1.5 g/L; concentration of multistage porous Pd/TiO2 catalyst of 3.5 g/L; Pd loading ratio of 1 wt%. Under these conditions, hydrogen production reached the value of 121.1 μmol in 4 h. Under the same conditions, replacing the kelp sacrificial agent with kelp treated with 4% alkali, resulted in a corresponding hydrogen production of 141.0 μmol in 4 h. Compared to other common biomass sacrificial agents, the use of kelp as a sacrificial agent for photocatalytic water splitting demonstrates superior hydrogen production performance.

Statistical modeling and optimization of volatile fatty acids production by anaerobic digestion of municipal wastewater sludge.

Obtaining value-added products from renewable resources is limited by the lack of specific operating conditions optimized for the physico-chemical characteristics of the biomass and the desired end product. A mathematical model and statistical optimization were developed for the production of volatile fatty acids (VFAs) by anaerobic digestion of municipal sewage sludge. The experimental tests were carried out in triplicate and investigated a wide range of conditions: pH 9.5, 10.5, and 11.5; temperatures 25°C, 35°C, 45°C, and 55°C; primary sludge with organic loading (OL) of 10 and 14g VS (volatile solids); and digested sludge with 4 and 6g VS. Subsequently, a statistical search was performed to obtain optimal production conditions, then a statistical model of VFA production was developed and the optimal conditions were validated at pilot plant scale. The maximum VFA concentration predicted was 6975mg COD (chemical oxygen demand)/L using primary sludge at 25°C, initial OL of 14g VS, and pH 10.5. The obtained third-degree model (r2 = 0.83) is a powerful tool for bioprocess scale-up, offering a promising avenue for sustainable waste management and biorefinery development.

Optimization and purification of L-methioninase enzyme purified from clinical samples of Pseudomonas spp.

Background: This study focused on Pseudomonas aeruginosa, which secrete important enzymes in medical and pharmaceutical applications and are isolated from clinical samples. One of these enzymes is L-methioninase, the most desirable enzyme in the medical and industrial fields today since it converted L-methionine into methanethiol, ammonia, and alpha-ketobutyrate. Objectives: Evaluated the optimum conditions of L-methioninase production and then purified it. Methods: Pseudomonas samples were identified by microscopic and biochemical tests and confirmed with the VITEK2 system. After the L-methioninase production was examined, the optimal conditions for the production of L-methioninase (MGL) were established using clinical samples of P. aeruginosa. Additionally, MGL was purified from the supernatant of P.aeruginosa using ammonium sulfate precipitation, DEAE-cellulose, and Sephadex G150 accordingly. Results: There were 33 isolates of P.aeruginosa according to microscopic characteristics and biochemical tests, followed by the VITEK2 system to ensure identification. The optimization conditions were achieved when supplement media with sucrose 1% w\v, casein 1% w\v, pH 7, temperature 37oC, and incubation for 48hrs within the specific activity of 1.6, 3.3, 3.4, 3.4, and 3.5U\mg protein, respectively, and 4.6 fold the amount of the purified enzyme as compared to the crude enzyme. A single 55 kDa band on the SDS-PAGE indicates the enzyme is purified. Conclusions: P.aeruginosa can be an efficient source of L-methioninase, and this enzyme had better and higher specific activity after applying optimum conditions for it and purifying it.

Optimization of the anaerobic digestion process and the metabolic pathway of methanogenesis of Jerusalem artichoke straw with the mixed addition of iron filings and biochar

This study explored the feasibility of the mixed addition of iron filings and biochar in the anaerobic digestion of Jerusalem artichoke straw (JAS), using iron filings and biochar as mixed additives for mid-temperature batch anaerobic digestion experiments, and applied response surface methodology to investigate the interactive effects of different ratios of iron filings and biochar (FE/BC), solid content, and initial pH on the cumulative methane production from JAS. The results showed that the optimal conditions for methane production were an FE/BC of 2.45:7.55, an initial pH of 7.59, and a solid content of 8.80 %. Under these conditions, the cumulative methane production was 278.11 mL g−1 volatile solid (VS) contents, which was very close to the predicted value (286.42 mL g−1 VS), with a relative error of less than 5 %, indicating the effectiveness of the model. The optimized conditions with mixed addition (HB) exhibited good synergistic promotion, increasing cumulative methane production by 48.69 % compared to the control without additives and by 22.29 % and 29.57 % compared to the single addition of iron filings and biochar, respectively. Moreover, the HB treatment under optimized conditions achieved good economic benefits. Metagenomic analysis showed that the relative abundances of bacterial taxa including Fermentimonas, DMER64, Bacteroidetes_VadinHA17, unclassified Synergistaceae, Clostridium, Ruminiclostridium, and unclassified Anaerolineaceae were higher in HB samples, and Methanothrix was also enriched. Methane metabolism pathway analysis indicated that the anaerobic digestion of JAS with the mixed addition of iron filings and biochar enhanced the acetoclastic methane production pathway, thereby increasing methane production.

Evaluation of wear and friction properties of graphite modified Lubri polylactic acid with various infill fabricated by additive manufacturing techniques

AbstractThree‐dimension (3D) printing technology, also known as additive manufacturing, is a manufacturing technology that creates three‐dimensional objects by depositing material layer by layer, as opposed to subtractive manufacturing methods. However, the newness of the technology brings with it many unknowns. In particular, the raw materials used are constantly increasing. For this reason, testing each raw material used in many aspects and to determine the optimum production conditions is important for the wide use of 3D printing technology. These optimal conditions may be the parameters used to produce a material, and sometimes they can appear as a new material. In addition, the production of new materials with varying production parameters is fundamental research topic that requires comprehensive study. For all these purposes, in this study, a new material type known as Lubri PLA (LPLA) was selected and produced in different filling types and subjected to a series of friction and wear tests. Thus, it is aimed to determine the tribological properties of the material. Additionally, samples were produced in ten different infill types (grid, lines, triangels, hexagon, cubic, octal, zigzag, diagonal, diagonal 3D and gyroid) to show the effect of filler type on friction and wear behavior. These filler types were used for both PLA and Lubri PLA materials and a total of twenty samples were produced. Thereby, it is aimed to conduct a comprehensive study showing the effect of both material difference and filling type on friction‐wear behavior. Diameter deviations, hardness deviations, friction coefficient, temperature, specific wear rates (SWr), and vibration were selected as output parameters. According to the analysis of the test results, the best result in terms of material structure was given by Lubri PLA, while the best result in terms of filling type was obtained with Diagonal 3D filling type. In addition, the lowest vibration level was obtained in the LP‐Diagonal 3D sample with 0.041 mm/s2, while the highest vibration level was obtained in the P‐Grid sample with 1.756 mm/s2.Highlights LPLA closed to nominal value in diameter and hardness deviations Addition of graphite nanoparticle increased the dimensional accuracy Diagonal 3D infill type Lubri PLA composites showed the superior performance Graphite modified Lubri PLA composites demonstrated superior performance

Optimization of Lipid Production of Rhodosporidium toruloides from Various Substrates

Background and Aim: In recent years, bioenergy has received a lot of attention from a technical point of view due to its ability to use reversible resources and its applicability worldwide. Biodiesel is a non-toxic, safe, renewable, and degradable fuel that is obtained from natural sources, such as vegetable oils, food waste oils, animal fats, algae, and microorganisms. This study aimed to optimize the lipid production of Rhodosporidium toruloides as a biofuel from different substrates. Materials and Methods: In this experimental laboratory study, after lipid extraction from Rhodosporidium toruloides CECT1137, cell biomass, nitrogen, and sugar consumption were measured according to the Bly and Dyer method. Then, using gas chromatography, the produced lipid compounds were identified, and lipid production was optimized by the one-factor method (type of nitrogen source and KH2PO4) and the Taguchi method (carbon and nitrogen source, temperature, pH, centrifuge, and time). Finally, the feasibility of mutation was investigated using UV to optimize lipid production. Results: The amount of lipid produced by Rhodosporidium toruloides was 4.95 g/l, which, after optimization by the Taguchi method, reached 8.54 g/l. Cell biomass, residual nitrogen, and consumed sugar were measured as 14.05, 0.19, and 28.85 g/l, respectively. Optimal production conditions were estimated by Taguchi, including 80 g/l carbon source, 1 g/l nitrogen source, 25 ° C, pH = 5.5, centrifuge at 180 rpm, and 96 hours. Most lipids produced were oleic acid and palmitic acid. Lipid production increased after UV exposure. Conclusion: The results showed that Rhodosporidium toruloides can accumulate a significant amount of lipid in its cells and can be a good alternative to plants and other sources of fuel production.

Process optimization in the pyroconversion of native sweet potato starch: structural and functional characterization of pyrodextrin

This work aims to produce dextrin from sweet potato (Ipomoea batatas) starch by pyroconversion. The effect of dextrinization process (roasting time, temperature, and hydrochloric acid concentration) on properties (structural and functional) of starch have been studied using central composite design of experiment. Reaction conditions included: roasting time (55 and 94 min), temperature (127 and 152 °C), and hydrochloric acid concentration (0.17 and 0.43 M). The temperature (quadratic effect X22) is highly significant on the three measured responses (p < 0.05) (Color Index (CI), Turbidity (Turb), and Saccharification Percentage (SP)). Also, the findings indicated that the two most important parameters influencing the pyroconversion of sweet potato starch in the current study were temperature (X2) and hydrochloric acid concentration (X3). The optimal conditions for dextrin production obtained are 94 min, 127 °C and 0.43 M for roasting time, temperature, and hydrochloric acid concentration respectively having 97% of solubility. The FTIR analysis revealed that OH, C-H, C-O, C–C and C-O–H were the main functional groups. These functional groups remained unaffected by the pyroconversion, since the bands extend and the spectrums of all native and pyrodextrin were similar. X-Ray Diffractometry analysis results of dextrin showed that the thermal treatment reduces the crystallinity of starch. Also, this analysis shows starch has CA-type XRD patterns. Scanning Electron Microscopy (SEM) analysis results showed that the defined optimal production maintains the morphology of starch. Differential scanning calorimetry (DSC) used for thermal analysis helps to obtain the glass transition temperature of modified starch equals to 139 °C. Optimal conditions of production of pyrodextrins from sweet potato granule starches could be easily produced with improved physicochemical properties to be used as encapsulating agent or additives in food and chemical industries.

Study of optimal nutritional conditions for Arbutin production from Bacillus subtilis NN2M

Arbutin is a combination of D-glucose and hydroquinone. Among the positive effects of arbutin are its antioxidant properties, antimicrobial properties and anti-inflammatory properties. Arbutin is one of the most important active compounds used to inhibit the enzyme tyrosinase, which causes enzymatic browning in many foods. Microbial fermentation has emerged as an up-and-coming technique for the production of arbutin in recent years. The aim of the study was the biological production of arbutin from Bacillus subtilis NN2M isolates. The isolates were confirmed and identified by Vitek and 16S rRNA and the nutritional conditions for production were improved to reach optimal conditions. To determine the best nutritional conditions for arbutin production, several conditions were studied, including the carbon source and its concentration, the nitrogen source and its concentration and the hydroquinone concentration. The results showed that the highest output of the active compound arbutin when using Molasses as a carbon source arbutin concentration was 23.34µg/mL. We also found the best concentration of the optimal carbon source, 4 % (w\v) arbutin concentration, was 27.62 µg/mL; furthermore, while using several nitrogen sources for producing arbutin, peptone was determined to be the optimum source, the concentration of arbutin was 47.3 µg/mL, the nitrogen source optimal Concentration was 2 % (w\v) arbutin concentration was 59.46 µg/mL, the optimum concentrations of hydroquinone was 2 % (w\v) arbutin concentration was 79.1 µg/mL.

Improved flame retardancy and mechanical properties of bacterial cellulose fabrics via solvent exchange and entrapment of zein and gluten

This study aimed to improve the flame retardancy and mechanical properties of bacterial cellulose (BC) by introducing cereal proteins, namely zein and gluten. The production conditions were determined by observing residual masses of samples at 1000 ℃ using thermogravimetric analysis (TGA). According to the TGA results, the optimized production conditions for the BCs with zein and gluten were combined solvent exchange and entrapment of 20 weight% (wt.%) of zein, and entrapment of 40 wt.% of gluten, respectively. Surface characterization of BC prepared with zein and gluten under the optimal conditions confirmed that the cereal proteins were incorporated into the BC nanostructures via solvent exchange and/or entrapment and the original chemical and crystal structures of BC were not significantly changed. Limiting oxygen index (LOI) analysis confirmed that cereal proteins improved the flame retardancy of BC. In particular, the LOI of BC entrapped with gluten was 50%, which was better than that of cowhide leather. Char morphology analysis confirmed that the as-produced BCs with cereal proteins exhibited condensed-phase flame-retardant mechanism by forming intumescent chars. Analysis of the mechanical properties confirmed that compared with cowhide leather, as-produced BCs with cereal proteins possessed high tensile strength and dimensional stability, making them suitable leather substitutes.

Microbial Biosynthesis of Medium-Chain-Length Polyhydroxyalkanoate (mcl-PHA) from Waste Cooking Oil.

Waste cooking oil is a common byproduct in the culinary industry, often posing disposal challenges. This study explores its conversion into the valuable bioplastic material, medium-chain-length polyhydroxyalkanoate (mcl-PHA), through microbial biosynthesis in controlled bioreactor conditions. Twenty-four bacterial isolates were obtained from oil-contaminated soil and waste materials in Mahd Ad-Dahab, Saudi Arabia. The best PHA-producing isolates were identified via 16S rDNA analysis as Neobacillus niacini and Metabacillus niabensis, with the sequences deposited in GenBank (accession numbers: PP346270 and PP346271). This study evaluated the effects of various carbon and nitrogen sources, as well as environmental factors, such as pH, temperature, and shaking speed, on the PHA production titer. Neobacillus niacini favored waste cooking oil and yeast extract, achieving a PHA production titer of 1.13 g/L, while Metabacillus niabensis preferred waste olive oil and urea, with a PHA production titer of 0.85 g/L. Both strains exhibited optimal growth at a neutral pH of 7, under optimal shaking -flask conditions. The bioreactor performance showed improved PHA production under controlled pH conditions, with a final titer of 9.75 g/L for Neobacillus niacini and 4.78 g/L for Metabacillus niabensis. Fourier transform infrared (FT-IR) spectroscopy and gas chromatography-mass spectrometry (GC-MS) confirmed the biosynthesized polymer as mcl-PHA. This research not only offers a sustainable method for transforming waste into valuable materials, but also provides insights into the optimal conditions for microbial PHA production, advancing environmental science and materials engineering.