Sugar cassettes

The first of these sugar cassette plasmids, pLN2 [67], contains seven genes (oleVWUYLSE) from the oleandomycin pathway of S. antibioticus involved in the biosynthesis of NDP-L-oleandrose 20. In order to facilitate the expression and exchange of genes on the cassette plasmid, another plasmid, pFL942, which... 

Table 1 The sugar cassette plasmids derived from pLN2 and pFL942...

Erythromycin A 64 and spinosyns A and D 65a/65b are important macrolides produced by Saccharopolyspora erythraea and Sacch. spinosa, respectively. Compound 65a contains per-O-methylated L-rhamnose and D-forosamine attached O-glycosidically to the aglycone. Gene knockouts in respective strains as well as expression of various sugar cassettes (along with appropriate GT gene(s)) in Sacch. erythraea mutants led to production of many derivatives of 64 and 65a and tylosin [111-114],... 

Diffusion. The cassettes are fed into the diffuser by means of a continuous weigher. Countercurrent hot water is introduced at the upper end of the diffuser. The extracted sugar leaves from the lower end of the diffuser as a grayish-black 10 to 15 percent sucrose solution called diffusion or raw juice. The extracted pulp is discharged at the top. The pulp contains residual sugar of approximately 0.2 percent of the beet dry weight. The pulp is pressed, dried, and enriched by the addition of 2 to 3 percent molasses. It serves as cattle feed. 

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