Production and Characterisation of an Exopolysaccharide by Bacillus amyloliquefaciens: Biotechnological Applications

Abstract

The Bacillus amyloliquefaciens RT7 strain was isolated from an extreme acidic environment and identified. The biodegradation capabilities of the strain using different carbon sources (glucose, oleic acid, Tween 80, PEG 200, and the combination of glucose–Tween 80) were evaluated via an indirect impedance technique. The glucose–Tween 80 combination was further studied using nuclear magnetic resonance (NMR). The exopolysaccharide (EPSRT7) that had been produced with the strain when biodegrading glucose–Tween 80 was isolated and characterised using different techniques (GC–MS, HPLC/MSMS, ATR–FTIR, TGA, and DSC), and its molecular weight was estimated. The results show that the average molecular weight of EPSRT7 was approximately 7.0794 × 104 Da and a heteropolysaccharide composed of mannose, glucose, galactose, and xylose (molar ratio, 1:0.5:0.1:0.1) with good thermostability. EPSRT7 showed good emulsifying activity against different natural oils and hydrocarbons at high concentrations (2 mg/mL) and at the studied pH range (3.1–7.2). It also presented good emulsifying activity compared to that of commercial emulsifiers. Lastly, EPSRT7 showed antioxidant capacity for different free radicals, a lack of cytotoxicity, and antioxidant activity at the cellular level. EPSRT7 has promising applications in bioremediation processes and other industrial applications.

Biodegradation of Choline NTF2 by Pantoea agglomerans in Different Osmolarity. Characterization and Environmental Implications of the Produced Exopolysaccharide

“…The peak at 1600 cm −1 and 1401 cm −1 was attributed to the ionic carboxyl group (COO-) and C-H bond vibration, respectively [75]. According to a previous study, the absorption at 1246 cm −1 could be attributed to the pyranose ring [37]. Absorption peaks in the 1160 cm −1 region indicated C-O-C stretching vibration and the peak at 1018 cm −1 was due to C-O-H stretching vibration [76].…”

“…However, the EPS obtained from 0.6 M Choline NTF2, presented 47% higher activity than the other EPSs for vegetable oils, and even higher in hydrocarbons, with a 60% increase in emulsifying activity for 0.6 M Choline NTF2. This indicated that the morphology of the EPS had a decisive role in this activity [37]. The results indicated that at a concentration of 1 mg, the EPS only presented a better emulsifying (p < 0.05) activity for diesel ((E24) 60%) compared with commercial emulsifiers (Triton X-100 ((E24) 50%), Tween 20 ((E24) 50%) and SDS ((E24) 37.5%)).…”

“…Gas chromatography (EVOQ GC-TQ, Bruker) coupled with a mass spectrometry detector (GC-MS) was used to determine monosaccharides following the procedure described in the literature [37]. EPS was hydrolyzed at 120 • C for 2 h with 0.5 M trifluoroacetic acid (TFA).…”

“…Nonenzymatic antioxidants assays for 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH•), hydroxyl radical (•OH), and superoxide anion (O 2 − •) were evaluated as indicators of the free radical scavenging activities of the EPS at different concentrations (0.1, 0.25, 1.0, 2.5, 5.0, 7.5 and 10 mg/mL). The tests were carried out following the calculations and the procedure described in Sánchez-León et al [37]. The DPPH assay was carried out with different concentrations of EPS (50 µL) that were mixed with 100 µL of DPPH (100 µM DPPH-ethanolic solution).…”

“…However, the EPS obtained from 0.6 M Choline NTF 2 , presented 47% higher activity than the other EPSs for vegetable oils, and even higher in hydrocarbons, with a 60% increase in emulsifying activity for 0.6 M Choline NTF 2 . This indicated that the morphology of the EPS had a decisive role in this activity [37]. )) have been used as instruments to explore the antioxidant activity of exopolysaccharides [84].…”