Production of 2,3-butanediol by Klebsiella pneumoniae BLh-1 and Pantoea agglomerans BL1 cultivated in acid and enzymatic hydrolysates of soybean hull.

We investigated the production of 2,3-butanediol by two enterobacteria isolated from an environmental consortium, Klebsiella pneumoniae BLh-1 and Pantoea agglomerans BL1, in a bioprocess using acid and enzymatic hydrolysates of soybean hull as substrates. Cultivations were carried out in orbital shaker under microaerophilic conditions, at 30°C and 37°C, for both bacteria. Both hydrolysates presented high osmotic pressures, around 2,000 mOsm/kg, with varying concentrations of glucose, xylose, and arabinose. Both bacteria were able to grow in the hydrolysates, at both temperatures, and they efficiently converted sugars into 2,3-butanediol, showing yields varying from 0.25 to 0.51 g/g of sugars and maximum 2,3-butanediol concentrations varying from 6.4 to 21.9 g/L. Other metabolic products were also obtained in lower amounts, notably ethanol, which peaked at 3.6 g/L in cultures using the enzymatic hydrolysate at 30°C. These results suggest the potential use of these recently isolated bacteria to convert lignocellulosic biomass hydrolysates into value-added products.

The optimization of biohydrogen production by bacteria using residual glycerol from biodiesel synthesis.

In this research the production of hydrogen by Klebsiella pneumoniae BLb01 using residual glycerol discharged from a biodiesel fuel production plant was investigated. Klebsiella pneumoniae BLb01 was isolated from a bacteria-rich sludge of an upflow anaerobic sludge blanket reactor (UASB) of a soybean processing plant. A Plackett-Burman design (P-B) and Response Surface Methodology (RSM) were employed to determine the optimal condition for enhanced hydrogen production. The maximal hydrogen production, which was 45.0 mol % and with 98% of glycerol degradation, was achieved with the optimized medium with the following composition: 30 g L(-1) glycerol; 3 g L(-1) yeast ex tract 3 g L(-1) K(2)HPO(4); 1 g L(-1) KH(2)PO(4); temperature 39°C and pH 9.0. These results show the ability of this new strain of effectively converting residual glycerol into value-added energy products.