This work had as its main objective to contribute to the development of a biological detoxification of hemicellulose hydrolysates obtained from different biomass plants using Issatchenkia occidentalis CCTCC M 206097 yeast. Tests with hemicellulosic hydrolysate of sugarcane bagasse in different concentrations were carried out to evaluate the influence of the hydrolysate concentration on the inhibitory compounds removal from the sugarcane bagasse hydrolysate, without reduction of sugar concentration. The highest reduction values of inhibitors concentration and less sugar losses were observed when the fivefold concentrated hydrolysate was treated by the evaluated yeast. In these experiments it was found that the high sugar concentrations favored lower sugar consumption by the yeast. The highest concentration reduction of syringaldehyde (66.67%), ferulic acid (73.33%), furfural (62%), and 5-HMF (85%) was observed when the concentrated hydrolysate was detoxified by using this yeast strain after 24 h of experimentation. The results obtained in this work showed the potential of the yeast Issatchenkia occidentalis CCTCC M 206097 as detoxification agent of hemicellulosic hydrolysate of different biomass plants.

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In this paper, two new strians, Issatchenkia occidentalis (Lj-3, CCTCC M 2006097) and Issatchenkia orienalis (S-7, CCTCC M 2006098), isolated from different environments on solid media, were used in the detoxification process of the hemicellulosic hydrolysate of sugarcane bagasse. High-pressure liquid chromatography elution curve of UV-absorption compounds represented by acetic acid, furfural, and guaiacol (toxic compounds found in the hemicellulosic hydrolysate) showed that several chromatographic peaks were evidently diminished for the case of detoxified hydrolysate with isolate strains compared to the high peaks resulted for no detoxified hydrolysate. It was clear that these inhibitors were degraded by the two new isolates during their cultivation process. Fermentation results for the biodetoxified hydrolysate showed an increase in xylitol productivity (Q (p)) by 1.97 and 1.95 times (2.03 and 2.01 g l(-1) h(-1)) and in xylitol yield (Y (p)) by 1.72 and 1.65 times (0.93 and 0.89 g xylitol per gram xylose) for hydrolysate treated with S-7 and Lj-3, respectively, in comparison with no detoxified hydrolysate (1.03 g l(-1) h(-1) and 0.54 g xylitol per gram xylose). This present work demonstrated the importance of Issatchenkia yeast in providing an effective biological detoxification approach to remove inhibitors and improve hydrolysate fermentability, leading to a high xylitol productivity and yield.

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Lo Han Kuo is the fruit of the Siraitia grosvenori SWINGLE (formerly Momordica grosvenori SWINGLE) belonging to Cucurbitaceae species and used as a pulmonary demulcent and emollient for the treatment of dry cough, sore throat, dire thirst, and constipation in traditional Chinese medicine.1) Recently, some intriguing pharmacological characteristics such as anti-cancer and anti-hyperglycemic effects, and inhibition of oxidative modification of low density-lipoprotein were reported.2-4) Therefore it was suggested that a new kind of cancer chemopreventive agent might be developed. A number of cucurbitane triterpene saponins from the ripe fruits were previously obtained. [5][6][7][8][9][10][11][12] Some compounds among them are extremely sweet, such as mogroside V (7) and mogroside IVA (6), and their relative sweetnesses were more than 300 times as high as that of sucrose despite having minimal caloric content. However, it also contains minor tasteless, even bitter principle, such as mogroside III (5) and mogroside IIE (4). The ripe fruit mainly contains mogroside V (7), so it is very sweet. On the basis of these characteristics, its extract is commercially utilized as a sweet component in sugar substitute, that is widely used as additive and ingredient in health foods and beverages. Owing to the influence of cold weather during winter, some fruits cannot mature naturally. The unripe fruits have bitter taste, and at the place of cultivation, these may amount to one quarter of total production. Until now, no chemical constituent studies have been conducted on these fruits. Hence in unripe fruits, a study on the constituents was performed and provided two new cucurbitane triterpene glycosides, 20-hydroxy-11-oxomogroside IA 1 (1) and 11-oxomogroside IIE (2), along with five known cucurbitane glycosides, 11-oxomogroside IA 1 (3), mogroside IIE (4), mogroside III (5), mogroside IVA (6), mogroside V (7), and two flavonoid glycosides, kaempferol 7-O-a-L-rhamnopyranoside (8) and kaempferol 3,7-di-O-a-L-rhamnopyranoside (9). Their structures were determined on the basis of detailed analyses of 1D, 2D-NMR spectroscopic methods and by comparing with literature values.4-11) Compounds 2 and 4 are the main constituents of unripe fruits and contribute to bitter taste. This paper deals with the first investigation of unripe bitter Lo Han Kuo fruits.Fresh unripe fruits were extracted with methanol. A suspension of methanol-extract in water was subjected to a high-porous polystynene gel, Diaion HP-20, which was successively eluted with H 2 O and 30%, 80%, and 100% methanol. The 80% methanolic eluate was chromatographed on silica gel, Sephadex LH-20 and reverse phase silica gel to afford nine glycosides, compounds 1-9, in yields of 0.0002%, 0.0068%, 0.00064%, 0.0081%, 0.0024%, 0.00019%, 0.0005%, 0.00081% and 0.0011%, respectively.Compound 1, a white amorphous powder, [a] D ϩ113.3°( MeOH), showed a quasi-molecular ion peak at m/z 654 [MϩH] ϩ and 654.4398 [MϩH] ϩ in the positive HR-FAB-MS, corresponding to the molecular formula C 36 ...

Terpenes U 0200Cucurbitane Glycosides from Unripe Fruits of Lo Han Kuo (Siraitia grosvenori).-Two new cucurbitane triterpene glucosides, 20-hydroxy-11-oxomogroside IA 1 (I) and 11-oxomogroside IIE (II), are isolated from the unripe fruits of Lo Han Kuo (Siraitia grosvenori) thogether with five known cucurbitane glucosides.-(LI*, D.; IKE-DA, T.; MATSUOKA, N.; NOHARA, T.; ZHANG, H.; SAKAMOTO, T.; NONAKA, G.-I.; Chem.

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