Optimization of Novel Extracellular Polysaccharide Production by an Enterobacter sp, on Wood Hydrolysates

An environmental isolate identified as Enterobacter cloacae has been found to produce a highly viscous, anionic extracellular polysaccharide (EPS) from a weak mineral acid hydrolysate of hardwood. Production of this EPS has been optimized on the hydrolysate (initial pH, 6.3; NH(4)Cl amendment, 0.1%) so that crude yields approaching 9.83 g/liter were obtained. Although this EPS is polydisperse, its molecular mass as determined by gel exclusion chromatography centers at approximately 1,700 kDa. Solutions of this EPS have been examined rheologically under a variety of conditions and compare favorably with both xanthan and alginate.