The invention provides biosynthetic routes to xylitol production that do not require pure D-xylose for synthesis and that can utilize inexpensive substrates such as hemicellulose hydrolysates.

Methods for production of xylitol in microorganisms

Transgenic plants and methods of culturing them using sorbitol as a sole carbon source are provided. One embodiment provides a method and system for positively selecting transgenic plants carrying and expressing a gene of interest. The transgenic plants are engineered to express sorbitol dehydrogenase in an amount effective to allow the transgenic plant to grow using sorbitol as the sole carbon source. In a preferred embodiment, the plant to be transformed does not have endogenous sorbitol dehydrogenase activity. Representative plants that can be transformed, include but are not limited to members of the Brassica family, industrial oilseeds, Arabidopsis thaliana, algae, soybean, cottonseed, sunflower, palm, coconut, rice, safflower, peanut, mustards, silage corn, alfalfa, switchgrass, miscanthus, sorghum, tobacco, sugarcane and flax.

Method of positive plant selection using sorbitol dehydrogenase

Provided is Metschnikowia strain designated as International Depositary Authority of Canada (ID AC) Accession Number 081116-01, and strains derived therefrom expressing at least one xylose reductase, at least one xylose transporter, and comprising a genetic modification that attenuates xylitol dehydrogenase, for use in the production of xylitol from xylose, and composition and method for production of xylitol therefrom.

Xylitol producing metschnikowia species

Disclosed herein are novel methods and materials for selecting transgenic cells. Specifically exemplified herein are positive selection methods that involve conferring to cells the ability to metabolize certain compounds, preferably arabitol, ribitol, raffinose, sucrose, mannitol or combinations thereof. Accordingly, transformed cells can be selected by simply subjecting them to a medium containing such compounds. The subject invention alleviates the disadvantages and concerns of negative selection methods, such as the unnecessary killing of transformed cells and the dispersal of potentially harmful genes (e.g., antibiotic or herbicide resistant genes) into the environment. Furthermore, novel nucleotide sequences relating to the E. coli rtl operon and arabitol dehydrogenase gene, and amino acid sequences relating to the gene products thereof are disclosed.

Patrick Kane

Papers

Arabitol or ribitol as positive selectable markers