Biosynthesis of exopolysaccharide from waste molasses using Pantoea sp. BCCS 001 GH: a kinetic and optimization study

Abstract

The bacterium Pantoea sp. BCCS 001 GH produces an exopolysaccharide (EPS) named Pantoan through using sugar beet molasses (SBM) as an inexpensive and widely available carbon source. This study aims to investigate the kinetics and optimization of the Pantoan biosynthesis using Pantoea sp. BCCS 001 GH in submerged culture. During kinetics studies, the logistic model and Luedeking–Piret equation are precisely fit with the obtained experimental data. The response surface methodology (RSM)-central composite design (CCD) method is applied to evaluate the effects of four factors (SBM, peptone, Na2HPO4, and Triton X-100) on the concentration of Pantoan in batch culture of Pantoea sp. BCCS 001 GH. The experimental and predicted maximum Pantoan production yields are found 9.9 ± 0.5 and 10.30 g/L, respectively, and the best prediction factor concentrations are achieved at 31.5 g/L SBM, 2.73 g/L peptone, 3 g/L Na2HPO4, and 0.32 g/L Triton X-100 after 48 h of submerged culture fermentation, at 30 °C. The functional groups and major monosaccharides (glucose and galactose) of a purified Pantoan are described and confirmed by 1HNMR and FTIR. The produced Pantoan is also characterized by thermogravimetric analysis and the rheological properties of the biopolymer are investigated. The present work guides the design and optimization of the Pantoea sp. BCCS 001 GH culture media, to be fine-tuned and applied to invaluable EPS, which can be applicable in food and biotechnology applications.

Sustainable Exopolysaccharide Production by Rhizobium viscosum CECT908 Using Corn Steep Liquor and Sugarcane Molasses as Sole Substrates

“…The presence of a high concentration of residual sugar in the culture medium is in accordance with previous reports [ 16 , 18 , 38 , 39 ]. Contrarily, other EPS-producing strains exhibit sugar consumption rates higher than 90% [ 8 , 17 , 19 , 22 , 24 , 25 ].…”

“…The molasses used in this work contained sucrose (435 ± 8 g/kg), glucose (119 ± 5 g/kg) and fructose (51 ± 2 g/kg). Besides carbohydrates, sugarcane molasses contains metal ions (calcium, cooper, iron, magnesium, manganese, phosphorous, potassium and sodium), vitamins, organic acids and amino acids, which improve bacterial growth [ 8 , 22 , 38 , 40 ].…”

“…Microbial exopolysaccharides (EPS) have a wide range of potential uses in the food, pharmaceutical, cosmetics and petroleum industries, among others, where they can act as thickening, film-forming, gelling, emulsion-stabilizing, flocculating, texture-improving or mobility control agents [ 1 , 2 , 3 , 4 , 5 , 6 ]. Although synthetic polymers and biopolymers derived from plants dominate the global market, microbial EPS (e.g., xanthan gum, gellan gum, levan, dextran, scleroglucan, curdlan, pullulan) have garnered increasing interest in the recent years [ 3 , 7 , 8 ]. For example, the global xanthan gum market is expected to grow from 1000 million USD in 2019 to 1500 million USD in 2027 [ 9 ].…”

“…Microbial EPS usually exhibit remarkable biological activities (e.g., antitumor, antimicrobial, antioxidant, anti-inflammatory, immunomodulatory or prebiotic activity) that are not present in synthetic polymers [ 1 , 7 , 9 , 15 ]. Therefore, some of them could be incorporated in high-value products such as pharmaceuticals, cosmetics, medical devices or functional foods [ 1 , 3 , 8 , 16 , 17 ].…”

“…Therefore, the use of alternative low-cost substrates is crucial to reduce the price of the final product. Accordingly, several wastes and by-products generated by agro-industrial processes have been assessed as inexpensive substrates for EPS production by various microorganisms [ 4 , 8 , 12 , 13 , 15 , 16 , 17 , 19 , 21 , 22 ].…”