A novel bacterial strain of acetic acid bacteria capable of producing riboflavin was isolated from the soil sample collected in Wuhan, China. The isolated strain was identified as Gluconobacter oxydans FBFS97 based on several phenotype characteristics, biochemicals tests, and 16S rRNA gene sequence conducted. Furthermore, the complete genome sequencing of the isolated strain has showed that it contains a complete operon for the biosynthesis of riboflavin. In order to obtain the maximum concentration of riboflavin production, Gluconobacter oxydans FBFS97 was optimized in shake flask cultures through response surface methodology employing Plackett–Burman design (PBD), and Central composite design (CCD). The results of the pre-experiments displayed that fructose and tryptone were found to be the most suitable sources of carbon and nitrogen for riboflavin production. Then, PBD was conducted for initial screening of eleven minerals (FeSO₄, FeCl₃, KH₂PO₄, K₂HPO₄, MgSO₄, ZnSO₄, NaCl, CaCl₂, KCl, ZnCl₂, and AlCl₃.6H₂O) for their significances on riboflavin production by Gluconobacter oxydans strain FBFS97. The most significant variables affecting on riboflavin production are K₂HPO₄ and CaCl₂, the interaction affects and levels of these variables were optimized by CCD. After optimization of the medium compositions for riboflavin production were determined as follows: fructose 25 g/L, tryptone 12.5 g/L, K₂HPO₄ 9 g/L, and CaCl₂ 0.06 g/L with maximum riboflavin production 23.24 mg/L.

Seaweed has different biologically active macromolecules, including polyphenols, fiber, proteins, and polysaccharides. Recent developments in seaweed bioactive compounds improved food packaging quality and functional properties and increased food production innovations and sustainability. Seaweed compounds are a good source of gelling, thickening, and emulsifying agents in food industrial products. Further Green Extraction methods are used for the extraction of bioactive compounds, these methods are environment friendly, with less time and high-yield production. Seaweeds incorporate antioxidants that reduce lipid oxidation, thus enhancing food's durability and nutritional value and reducing free radicals' occurrence and retard the growth of bacteria. Seaweed has increased its potential for antimicrobial packaging solutions. The manuscript explores the perspective for advancing seaweed-based films, involving property improvements, increased shelf life, and production scalability. Seaweed-based films offer sustainable packaging for fresh produce, seafood, bakeries, and confectionery products. Seaweed-derived bioactive compounds enhance the quality and safety of packaged food products and seaweed polysaccharides in food packaging are their biodegradability and environmental friendliness. Graphical Abstract

The present study aimed to characterize melanin pigment extracted from Gluconobacter oxydans FBFS 97. After 14 days of culture at 28 °C in GY (glucose and yeast extract) liquid-state medium, G. oxydans FBFS97 produce the maximum melanin, up to about 12–15 mg/L. The physicochemical characteristics of the extracted melanin showed an ability to dissolve in 1 mol/L NaOH or 1 mol/L KOH, and insolubility in water and most organic solvents, such as chloroform and petroleum ether. The extracted melanin was confirmed to be exact melanin by ultraviolet-visible spectrophotometry, Fourier-transform infrared spectroscopy, thin-layer chromatography, elemental analysis, and scanning electron microscopy. The UV-visible spectrum of G. oxydans FBFS97 exhibited a maximum absorption peak at 230 nm. Extracted melanin demonstrated significant free radical-scavenging activity by DPPH and ABTS methods. The IC₅₀ value of the extracted melanin for scavenging 50% DPPH radicals was 36.94 μg/mL, and the IC₅₀ value of antioxidant activity for ABTS was 4.06 μg/mL. Hence, G. oxydans FBFS97 has the potential to be a new candidate for melanin production.

Seaweeds are an excellent source of nutrients and bioactive compounds associated with health benefits. In this study, symbiotic beverages were prepared by submerged fermentation with Lactobacillus and SCOBY as fermented materials and using Eucheuma Cottonii seaweed. During fermentation, the quality characteristics were analyzed and the physicochemical (pH, acidity, sugar, and alcohol content), Total phenolic content (TPC), Total flavonoid content (TFC), antioxidant capacity (DPPH, FRAP) organoleptic properties (9-point hedonic scale) of seaweed beverages. The pH levels of Lacto-based (5.2 ± 1.64) and SCOBY-based beverages reached (4.5 ± 0.12) and acidity for (0.5 ± 0.06) and (0.9 ± 0.07) after 30 days of fermentation. Sugar content decreased, and alcohol content increased with an increase in the number of fermentation days. The protein content increased significantly (p < 0.05) during fermentation. However, Lacto-based beverages have a low protein content, and SCOBY-based beverages have a high protein content (0.25 mg/ml). SCOBY-based seaweed beverages have high flavonoids (29.44 ± 0.63) and phenolic contents (27.44 ± 0.02). The DPPH value of Lacto-based beverages is (61.23 ± 1.54%), SCOBY-based beverages are (61.98 ± 0.22%), and the FRAP value is (17.53 ± 0.08%) and (19.98 ± 0.08%) after 30 days of fermentation. The heavy metal content in seaweed beverages was below the standard value; therefore, it is safe for consumption. The results showed that SCOBY-based beverages have enhanced nutritional and improved sensory properties, indicating the possibility of commercialization. Graphical abstract

Journal of Medical Internet Research - International Scientific Journal for Medical Research, Information and Communication on the Internet #Preprint #PeerReviewMe: Warning: This is a unreviewed preprint. Readers are warned that the document has not been peer-reviewed by expert/patient reviewers or an academic editor, may contain misleading claims, and is likely to undergo changes before final publication, if accepted, or may have been rejected/withdrawn. Readers with interest and expertise are encouraged to sign up as peer-reviewer, if the paper is within an open peer-review period. Please cite this preprint only for review purposes or for grant applications and CVs (if you are the author). Background: There is a lack of investigation into the dynamics of blood lipids before, during, and after diurnal fasting, especially in inactive men. Objective: This study determined dynamic changes in blood lipids in inactive men before, during, and after they underwent diurnal fasting. Methods: A total of 44 young men aged a mean 27.6 (SD 5.8) years were recruited to evaluate their habitual physical activity and diet using a questionnaire developed for this study. Body composition was evaluated using a bioelectrical impedance analysis machine (Tanita BC-980). An 8-ml blood sample was collected to evaluate blood lipids and glucose. All measurements were taken 2-3 days before Ramadan, during Ramadan (at week 2 and week 3), and 1 month after Ramadan. A 1-way repeated measures ANOVA was used to compare the measured variables before, during, and after the month of Ramadan. When a significant difference was found, post hoc testing was used. Differences were considered significant at P<.05. Results: There was a significant reduction in low-density lipoprotein during Ramadan compared to before and after Ramadan (83.49 mg/dl at week 3 vs 93.11 mg/dl before Ramadan [P=.02] and 101.59 mg/dl after Ramadan [P=.007]). There were significant elevations in fasting blood glucose (74.60 mmol/L before Ramadan vs 81.52 mmol/L at week 3 [P=.03] and 86.51 mmol/L after Ramadan [P=.01]) and blood pressure (109 mm Hg before Ramadan vs 114 mm Hg after Ramadan; P=.02) reported during and even after the month of Ramadan, although both fasting blood glucose and blood pressure were within normal levels. Conclusions: Ramadan fasting could be an independent factor in reducing low-density lipoprotein. Further investigations are encouraged to clarify the impact of diurnal fasting on blood lipids in people with special conditions.

Seaweeds are an excellent source of nutrients and bioactive compounds associated with health benefits. In this study, symbiotic beverages were prepared by submerged fermentation with Lactobacillus and SCOBY as fermented materials and using Eucheuma Cottonii seaweed. During fermentation, the quality characteristics were analyzed and the physicochemical (pH, acidity, sugar, and alcohol content), Total phenolic content (TPC), Total flavonoid content (TFC), antioxidant capacity (DPPH, FRAP) organoleptic properties (9-point hedonic scale) of seaweed beverages. The pH levels of Lacto-based (5.2 ± 1.64) and SCOBY-based beverages reached (4.5 ± 0.12) and acidity for (0.5 ± 0.06) and (0.9 ± 0.07) after 30 days of fermentation. Sugar content decreased, and alcohol content increased with an increase in the number of fermentation days. The protein content increased significantly (p < 0.05) during fermentation. However, Lacto-based beverages have a low protein content, and SCOBY-based beverages have a high protein content (0.25 mg/ml). SCOBY-based seaweed beverages have high flavonoids (29.44 ± 0.63) and phenolic contents (27.44 ± 0.02). The DPPH value of Lacto-based beverages is (61.23 ± 1.54%), SCOBY-based beverages are (61.98 ± 0.22%), and the FRAP value is (17.53 ± 0.08%) and (19.98 ± 0.08%) after 30 days of fermentation. The heavy metal content in seaweed beverages was below the standard value; therefore, it is safe for consumption. The results showed that SCOBY-based beverages have enhanced nutritional and improved sensory properties, indicating the possibility of commercialization.