Mannitol yeasts

The strain Rhizobium EQ1 was used. This strain was isolated from culture of the beans variety "Caupi" from an arid region of the northeast of Brazil. This strain was kept in agar-mannitol-yeast extract (YMA) for several months, and, after its characterization was cataloged, at the culture bank of the School of Chemistry from Federal University of Rio de Janeiro, under the code EQ1. 

Media were devised that supported consistent growth of the rhizobia, and mannitol often was favored as the energy source in the media. Yeast extract commonly was added to supply micronutrients. Selection of effective strains of the rhizobia was an empirical process based on greenhouse and field testing. Usually, several effective strains were grown on liquid media and then mixed on a solid support for distribution. 

The initial pH of the medium was adjusted to 7.0. All chemicals were of analytical grade. The carbon sources (commercial sugar-sucrose, sugarcane juice and molasses, sugarcane juice alcohol stillage, glycerol, mannitol, soybean oil) were added in order to establish an initial substrate concentration of 20 g/L. In some cases, the medium was also aseptically supplemented with 0.1% (w/v) yeast extract and 0.001% (w/v) Na EDTA previously and separately sterilized by filtration through a Millipore membrane with a pore size of 0.22 pm. 

Figure 7. Radioactivity scan of an electrophoretogram of a NaB[3H]i reduced hydrolysate of mannose-6-phosphate (top) and a mannose-6-phosphate containing yeast phosphomannan (37) (bottom. The procedure is described in the text. The compounds migrating more rapidly than mannitol-6-phosphate are derived from decomposition of the Dowex-50 resin used to catalyze the hydrolysis. The migration of authentic mannitol and mannitol phosphate were determined by direct reduction of mannose and mannose-6-phosphate, respectively.

Costenoble, R., Adler, L., Niklasson, C., and Liden, G. 2003. Engineering of the metabolism of Saccharomyces cerevisiae for anaerobic production of mannitol. FEMS Yeast Res., 3,17-25. 

Candida of the monosaccharides D-galactose, L-sorbose, and D-xylose, as well as that of a number of alditols, namely, erythritol, D- and l-arabinitol, ribitol, xylitol, D-glucitol, and D-mannitol. The yeast was grown on succinate as the sole source of carbon, and so the carriers could be considered non-induced. The authors reported214 that the substrates enter by active transport by means of four carriers (i) the first has a high affinity for alditols (ii) the second has a high affinity for the monosaccharides (in) the third has a low affinity both for alditols and monosaccharides and (iv) the fourth is specific to erythritol and D-ribose, for both of which it has a high affinity. 

For succinate-grown yeast, extracts catalyze D-glucitol D-fiructose + L-xt/Zo-hexulose, D-mannitol <->D-fructose, D-arabinitol — threo-pentulose, and reduction of NAD with xylitol or erythritol.264... 

For D-xylose-grown yeast, extracts catalyze (i) xylitol D-xylose, (ii) L-arabinitol L-arabinose,884-885 (Hi) ribitol - D-ribose, (iv) galactitol D-galactose. Purified enzyme also (a) oxidizes NADPH with D-glucose, and (b) reduces NADP with D-glucitol, erythritol, or D-mannitol.809... 

For D-glucose-grown yeast, partly purified enzyme catalyzes erythritol — g/ycero-tetrulose, D-arabinitol - D-threo-pentulose, xylitol — threo-pentulose, ribitol — erythro-pentulose, D-glucitol — fructose, galactitol — tagatose, D-mannitol —> fiructose.612... 

For D-glucitol-grown yeast, extracts catalyze reduction of NADP with D-mannitol.2 4... 

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