Lactic acid bacteria have wide applications in food processing. Lactic acid bacteria produced exopolysaccharides (EPS) which could be used as possible replacer for commercial stabilizer and thickeners produced by nonfood grade bacteria. Seventy‐two samples of Oil and Raphia palm sap were collected in eighteen locations across South‐Western Nigeria and screened for exopolysaccharide production in 6% sucrose agar using streaked plate method. Four hundred EPS‐producing bacteria (EPB) isolated were clustered based on morphological characteristics into two broad groups and preliminary screened for EPS‐producing capacity. Twenty representative of EPB were selected from the broad groups for tentative identification by API 50CHL and 10 high yielding EPB were selected for large‐scale EPS production. Each strain was inoculated into 6% sucrose broth with 3% (v/v) preculture grown overnight in a 1.5 ml flask and incubated at 37°C for 72 hr. The EPSs were purified and freeze‐dried prior to quantification of yields. EPS‐producing bacteria were identified as Leuconostoc lactis, Lactobacillus fermentum, Lactobacillus delbrueckii ssp. lactis, L. delbrueckii ssp. delbrueckii, Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus crispatus, and Leuconostoc mesenteroides ssp. mesenteroides/dextranicum. EPS yield ranged from 132–810.75 mg/L and EPS‐producing potential of lactic acid bacteria (LAB) strains ranged; 36% (132–245 mg/L), 36% (250–460 mg/L), and 28% (461–820 mg/L). L. plantarum had the highest EPS yield of 810.75 mg/L whereas L. crispatus had the least yield 242.5 mg/L. These results suggest that majority of LAB in palm wine saps are gum‐producing bacteria. Leuconostoc and Lactobacillus were the most abundant LAB found in this study while L. plantarum could have applications as potential starter cultures for the production of exopolysaccharides (EPS) at industrial level.

Aims: This study evaluated the physical, chemical and rheological properties of exopolysaccharides (EPSs) produced by Lactic Acid Bacteria (LAB) isolated from palm wine. Materials and Methods: EPSs from palm wine LAB strains were produced on 6% sucrose broth, purified and freeze-dried prior to analyses.  Molecular weights (MW), rheological and structural composition (functional groups) of the EPSs were determined using standard methods and Fourier transform infrared spectroscopy (FTIR). Results: The average MW of the EPSs ranged from 2.02×106 to 6.53×106 Da while the flow index (n) values ranged from 0.03-3.13 at 0.2%, 0.06-1.51 at 0.4%, 0.38 - 1.85 at 0.6%, 0.14 - 2.26 at 0.8% and 0.55 - 6.42 at 1% concentrations at elevated temperatures for EPS solutions from the ten LAB species. The FTIR spectrum revealed prominent peaks of various groups of OH (3420 cm-1) and CH3 bending (2090 cm-1) in all the EPSs corresponding to both hydroxyl and amine groups, and aliphatic C-H bonds, respectively. EPS synthesized by Leuconostoc lactis, Lactococcus lactis subsp lactis and Lactiplantibacillus plantarum showed weak absorption peaks (1148 – 1145 cm-1) indicating the C-O-C and C-O bonds, while absorption peaks of Lactobacillus lactis, Lactobacillus acidophilus and Lactiplantibacillus plantarum (1267 – 1253 cm-1) indicated O- acetyl ester and other non-sugar components. Conclusions: The FTIR spectra, rheological properties and molecular weight of EPSs synthesized by the ten LAB strains indicated potentials that could be exploited in different industrial applications, and as stabilizers in food industries