Raw dataset for the production of antioxidant exopolysaccharides produced by Bacillus amyloliquefaciens KW8 using cassava pulp and nitrogen supplement optimized via Response Surface Methodology
Description
This raw dataset reflects an evaluation of the optimal nitrogen source for the production of antioxidant exopolysaccharides (EPSs) by Bacillus amyloliquefaciens KW8 using cassava pulp carbon source. Various nitrogen sources were initially screened, and yeast extract was identified as the most effective. Further optimization was conducted using Response Surface Methodology (RSM) with a Central Composite Design (CCD) to assess the influence of key parameters, including pH, inoculum size, carbon-to-nitrogen (C/N) ratio, and agitation speed on EPS production. The amount of EPS, media pH, reducing sugar level, and viable bacterial population after 3 days of fermentation were recorded. The EPS's structural characteristics were investigated using scanning electron microscopy (SEM). The levels of bioactive compounds and antioxidant capabilities in the EPS, such as its total phenolic content, total flavonoid content, ferric reducing antioxidant power, hydroxyl radical scavenging activity, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity were also measured. This experiment used microbial cell factories to convert cassava pulp, an agro-biowaste, into more valuable EPS bioproducts, which supports sustainable developmental goals.
Files
Steps to reproduce
Cassava pulp was milled, sieved into a fine powder, and stored in a desiccator for later use. Bacterial strains were cultured in Tryptic Soy Broth (TSB, pH 7.0) at 37°C and 150 rpm for 24 h. The cultures were adjusted to OD₆₀₀ = 0.1 and used as 5% (v/v) inocula. Four nitrogen sources—(NH₄)₂SO₄, yeast extract, NH₄Cl, and peptone—were initially screened at 5% (w/v) using cassava pulp as the carbon source (5% w/v) to identify the most effective for EPS production by Bacillus amyloliquefaciens KW8. Subsequent optimization employed a central composite design (CCD) using Response Surface Methodology (RSM) to study the effects of inoculum size (5–25%), C/N ratio (20–100), pH (4.0–8.0), and agitation speed (125–225 rpm) over a 3-day incubation. A total of 30 experimental runs were performed, including six center-point, eight axial, and sixteen factorial replicates. EPS production was assessed based on sugar consumption, pH change, and bacterial growth measured daily, with EPS harvested on day 3 via centrifugation at 16,100 g for 30 min at 4°C, ethanol precipitation, washing, and freeze-drying. Dried EPS (20 mg) was dissolved in sterile water and stored for further analysis. Antioxidant properties of EPS were determined using hydroxyl radical scavenging, DPPH, and FRAP assays. Total phenolic content (TPC) was quantified using the Folin–Ciocalteu method with gallic acid as standard, while total flavonoid content (TFC) was measured via colorimetric assay using rutin. EPS morphology was observed using SEM at 1000× and 2000× magnifications after gold coating. All experiments were performed in triplicate, and results were expressed as mean ± SD. Statistical analysis was conducted using ANOVA and Tukey’s HSD in SPSS Demon version, with significance considered at p < 0.05.
Institutions
- Mahasarakham University