Direct saccharification and ethanol fermentation of cello-oligosaccharides with recombinant yeast.

Ethanol was produced at good rates by direct saccharification and fermentation of cello-oligosaccharides with pYBGA1 yeast, a recombinant laboratory yeast expressing ß-glucosidase. Cellobiose in the concentration of 50 g/L was directly fermented for 60 h with 1×10(8) cells/mL of pYBGA1 yeast at 30 °C to give ethanol at an 80% theoretical conversion rate and a concentration of more than 20 g/L of concentration. Conversion to ethanol increased with increasing cellobiose concentration in the feed. When cellobiose was used at the concentration of 100g/L, ethanol conversion and concentration increased to 85% and 45 g/L, respectively, in 96 h incubation. Other cello-oligosaccharides, cellotriose, cellotetraose, and cellopentaose at the concentration of 50 g/L, respectively, were also fermented directly for 72 h with 1×10(8) cells/mL of pYBGA1 yeast to produce ethanol in the conversion rates and concentrations of 71-73% and 18.0-18.5 g/L, respectively. The direct saccharification and fermentation mechanism of cello-oligosaccharides with pYBGA1 yeast, as revealed by HPLC measurements, suggesting that cellotetraose, for example, was saccharificated to cellotriose, cellobiose, and glucose and then fermented to give ethanol. These results suggest that the direct saccharification and fermentation of cello-oligosaccharides with pYBGA1 has several advantages as a simple procedure and for time, cost, and energy consumptions.

Antihyperlipidemic compounds from the fruit of Piper longum L.

A bioassay-guided isolation of an ethanol extract of the fruit of Piper longum L. yielded piperlonguminine, piperine and pipernonaline, as the main antihyperlipidemic constituents. They exhibit appreciable antihyperlipidemic activity in vivo, which is comparable to that of the commercial antihyperlipidemic drug, simvastatin.

Chemo-enzymatic production of fuel ethanol from cellulosic materials utilizing yeast expressing beta-glucosidases.

Ethanol was produced in a considerably high yield by fermenting hydrolyzates from cellulosic materials by means of a recombinant laboratory yeast expressing beta-glucosidases. Tissue paper, cotton, and sawdust were hydrolyzed by two-step sulfuric acid hydrolysis to give mixtures containing glucose, cellobiose, and higher cello-oligosaccharides. After the cellulosic material was partially hydrolyzed with 80% sulfuric acid, the hydrolysis was continued with 5% sulfuric acid. Except for non-carbohydrate components, all constituents in the hydrolyzates were fermented by the yeast that was preincubated in the medium that the plasmid encoded by the beta-glucosidases gene was kept in the multiplicated yeast. A solution containing 4% hydrolyzates from paper was fermented to give as high as 1.9% maximum ethanol concentration and 70% ethanol conversion. Cotton also gave a similar result. Sawdust was converted into ethanol in approx 22% conversion. Accordingly, it was revealed that the beta-glucosidases-expressing yeast can ferment the cello-oligosaccharides obtained by hydrolysis of cellulosic materials into ethanol. In addition, a hydrolyzate containing a high glucose proportion gave a high ethanol concentration in a short time.