Dietary Administration Effects of Exopolysaccharide Produced by Bacillus tequilensis PS21 Using Riceberry Broken Rice, and Soybean Meal on Growth Performance, Immunity, and Resistance to Streptococcus agalactiae of Nile tilapia (Oreochromis niloticus).

Overuse of antibiotics in aquaculture has generated bacterial resistance and altered the ecology. Aquacultural disease control requires an environmentally sustainable approach. Bacterial exopolysaccharides (EPSs) as bioimmunostimulants have not been extensively explored in aquaculture. This study investigated EPS produced from 5% w/v riceberry broken rice as a carbon source and 1% w/v soybean meal as a nitrogen source by Bacillus tequilensis PS21 from milk kefir grain for its immunomodulatory, antioxidant activities and resistance to pathogenic Streptococcus agalactiae in Nile tilapia (Oreochromis niloticus). The FTIR spectrum of EPS confirmed the characteristic bonds of polysaccharides, while the HPLC chromatogram of EPS displayed only the glucose monomer subunit, indicating its homopolysaccharide feature. This EPS (20 mg/mL) exhibited DPPH scavenging activity of 65.50 ± 0.31%, an FRAP value of 2.07 ± 0.04 mg FeSO4/g DW, and antimicrobial activity (14.17 ± 0.76 mm inhibition zone diameter) against S. agalactiae EW1 using the agar disc diffusion method. Five groups of Nile tilapia were fed diets (T1 (Control) = 0.0, T2 = 0.1, T3 = 0.2, T4 = 1.0, and T5 = 2.0 g EPS/kg diet) for 90 days. Results showed that EPS did not affect growth performances or body composition, but EPS (T4 + T5) significantly stimulated neutrophil levels and serum lysozyme activity. EPS (T5) significantly induced myeloperoxidase activity, catalase activity, and liver superoxide dismutase activity. EPS (T5) also significantly increased the survival of fish at 80.00 ± 5.77% at 14 days post-challenge with S. agalactiae EW1 compared to the control (T1) at 53.33 ± 10.00%. This study presents an efficient method for utilizing agro-industrial biowaste as a prospective source of value-added EPS via a microbial factory to produce a bio-circular green economy model that preserves a healthy environment while also promoting sustainable aquaculture.

Data on exopolysaccharides produced by Bacillus spp. from cassava pulp with antioxidant and antimicrobial properties.

This data evaluated the capacity of Bacillus spp. isolated from Thai milk kefir to produce exopolysaccharide (EPS) on cassava pulp and tested its antioxidant and antibacterial properties. Thailand's starch industry generates million tons of cassava pulp, which is underutilized or bio-transformed into higher-value bioproducts. Antioxidant and antibacterial bacterial exopolysaccharides are beneficial in the food, feed, pharmaceutical, and cosmetic industries. Moisture, ash, fat, protein, fiber, starch, sugar, neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) were analyzed from cassava pulp as an EPS substrate. After 3 days of bacterial fermentation, EPS generation, culture pH, reducing sugar amount, and bacterial count were recorded. Antioxidant activities and bioactive content including hydroxyl radical scavenging activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP), total phenolic and flavonoid content (TPC and TFC), and antimicrobial activity against two Nile tilapia pathogens (Streptococcus agalactiae and Staphylococcus aureus) from different Bacillus species were evaluated. Proximate analysis, dinitrosalicylic acid assay, pH value record, bacterial count using spread plate method, antioxidant activity and bioactive content assays via spectrophotometry, and agar disk diffusion were the main approaches. This study used microbial cell factories to convert agro-biowaste, such as cassava pulp, into EPS bioproducts which accords with a bio-circular green economy model.

Effect of cold plasma and elicitors on bioactive contents, antioxidant activity and cytotoxicity of Thai rat-tailed radish microgreens.

BACKGROUND: Raphanus sativus var. caudatus or Thai rat-tailed radish (RTR) contains glucosinolates and isothiocyanates with chemopreventive effects; however, only mature plants have been investigated to date. Thus, the present study aimed to determine isothiocyanates, phenolic compounds and flavonoid compounds, antioxidant activity, cytotoxicity, and antiproliferative activity of RTR microgreens grown from seeds treated with cold plasma (21 kV for 5 min), organic elicitor (160 mmol L-1 NaCl, 10 mmol L-1 CaCl2 or 176 mmol L-1 sucrose) or both in combination. Seeds were germinated on vermiculite and sprayed with deionized water or elicitor for 7 days before harvest. RESULTS: Cold plasma had insignificant effect on growth, whereas NaCl and CaCl2 increased fresh weight. Plasma with CaCl2 led to the highest total isothiocyanate (ITC) content [1.99 g kg-1 dry weight (DW)] in RTR microgreens containing raphasatin as the only ITC detected. Plasma treatment gave the highest total phenolic content (7.56 mg gallic acid equivalents g-1 DW), antioxidant activity from a 2,2-diphenyl-1-picrylhydrazyl assay (7.70 mg trolox equivalents g-1 DW) and ferric reducing antioxidant power assay (21.72 mg Fe2+ g-1 DW). Microgreen extracts from plasma showed an IC50 value of 29.28 and 13.83 µg mL-1 towards MCF-7 and HepG2, respectively, with inhibitory properties on matrix metalloproteinase (MMP)-2 and MMP-9 proteins. Plasma enhanced Bax and Caspase-3 gene expression but reduced Bcl-2 and MMP-9 expression, indicating activation of apoptosis. CONCLUSION: Cold plasma shows promise as an innovative tool to enhance bioactive compounds with chemopreventive benefits in microgreens. © 2020 Society of Chemical Industry.

Formation of Sulforaphane and Iberin Products from Thai Cabbage Fermented by Myrosinase-Positive Bacteria.

Myrosinase-positive bacteria from local fermented foods and beverages in Thailand with the capacity to metabolize glucosinolate and produce isothiocyanates (ITCs) were isolated and used as selected strains for Thai cabbage fermentation. Enterobacter xiangfangensis 4A-2A3.1 (EX) from fermented fish and Enterococcus casseliflavus SB2X2 (EC) from fermented cabbage were the two highest ITC producers among seventeen strains identified by 16S rRNA technique. EC and EX were used to ferment Thai cabbage (Brassica oleracea L. var. capitata) containing glucoiberin, glucoraphanin and 4-hydroxyglucobrassicin at 430.5, 615.1 and 108.5 µmol/100 g DW, respectively for 3 days at 25 °C. Different amounts of iberin nitrile, iberin, sulforaphane and indole 3-acetonitrile were produced by spontaneous, EX- and EC-induced cabbage fermentations, and significantly higher ITCs were detected (p < 0.01) with increased antioxidant activities. Iberin and sulforaphane production in EX-induced treatment peaked on day 2 at 117.4 and 294.1 µmol/100 g DW, respectively, significantly higher than iberin at 51.7 µmol/100 g DW but not significantly higher than sulforaphane at 242.6 µmol/100 g DW in EC-induced treatment at day 2. Maximum health-promoting benefits from this functional food can be obtained from consumption of a liquid portion of the fermented cabbage with higher ITC level along with a solid portion.

Low cost medium for spore production of Bacillus KKU02 and KKU03 and the effects of the produced spores on growth of giant freshwater prawn (Macrobrachium rosenbergii de Man).

In order to extend the shelf life of 2 high potential Bacillus probiotic isolates which were Bacillus KKU02 and Bacillus KKU03, the spore forms of these 2 Bacillus isolates were studied for using as probiotic instead. The low cost medium for spore production of these 2 Bacillus isolates was examined in order to produce probiotic spores for feeding the shrimps. It was found that cassava at 100 g L(-1) and supplemented with 20.0 g L(-1) dextrose, 0.1 g L(-1) MgSO4 and 2.0 g L(-1) (NH4)2SO4 showed the highest spore concentration at about 1 x 10(8) CFU mL(-1). The effects of feeding these 2 Bacillus spores on the growth of giant freshwater prawns were further examined. The spores of Bacillus KKU02 and Bacillus KKU03 (-10(7) spore mL(-1)) in pure and mixed culture forms were mixed with commercial prawn feed (200 mL kg(-1)) to give six feed treatments. Body length and weight of the prawns in mixed spore culture tanks after rearing for 90 days (13.5 cm and 59.8 g, respectively) were significantly higher (p = 0.05) than other treatments. The treated prawns were further challenged with Aeromonas hydrophila for 7 days. The percentages of survival after the challenge in the prawns fed with the mixed spores (46.8%) were also found significantly higher (p = 0.05) than others groups, except the mixed live cell treatment (60%). These results indicated that the spores of Bacillus KKU02 and Bacillus KKU03 had a high potential for using as commercial probiotics.

Effect of feeding Bacillus sp. as probiotic bacteria on growth of giant freshwater prawn (Macrobrachium rosenbergii de Man).

The effects of feeding two Bacillus spp. isolated from the intestine of the giant freshwater prawn on the growth of Giant Freshwater Prawns (Macrobrachium rosenbergii de Man) was examined. The isolated Bacillus KKU02 and Bacillus KKU03 (approximately 10(7) CFU mL(-1)) were mixed into commercial prawn feed (200 mL kg(-1)). After rearing shrimp with the bacteria in four feed treatments, (Bacillus KKU03, Bacillus KKU02, mixed culture and control groups) for 120 days, body length and weight of the prawns in mixed culture tanks were significantly higher (p = 0.05) than in the control tanks (7.48 cm and 3.32 g, vs 6.6 cm and 2.1 g, respectively). Both isolates were found to produce amylase and protease. The stabilities of the single Bacillus sp., mixed culture and commercial probiotic in the feeds were examined during storage at 4 degrees C and room temperature. The percentage viability of Bacillus KKU02, Bacillus KKU03 and mixed culture stored at room temperature declined dramatically to 2.54, 21.88 and 10.92% within 2 weeks, respectively. At 4 degrees C however, the percentage viability of the tested probiotics reduced slowly. The survival of the commercial probiotics was the same at both temperatures about 50% after 70 days' storage.