T. Jeffries, M. Himmel
1998
Citations
0
Influential Citations
5
Citations
Journal
Journal name not available for this finding
Abstract
The applied biological research session has traditionally emphasized novel approaches to long- standing problems. This year most of the novelty emerged from metabolic and enzyme engineering. Increasingly, genetically engineered enzymes or organisms with altered traits are being integrated into processes. Fermentation of xylose by genetically engineered bacteria and yeast continues to attract attention. The high ethanol yield Zymomonas mobilis characteristically attains on glucose was shown to extend to the fermentation of glucose/xylose sugar mixtures in continuous cultures with strains that had been genetically engineered to express a xylose metabolic pathway. This consisted of xylose isomerase, xylulokinase, transketolase, and transaldolase. These studies indicate that there is no inherent technical barrier to further scale-up of continuous fermentations with this organism. Other research in this field has resulted in the development of an engineered Z. mobilis strain that will coferment arabinose. Increasing attention is being given to the use of hydrolysates by Z. mobilis and other ethanologens. Also, a number of yeasts have been screened and adapted to the fermentation of softwood prehydrolysates. The nature of the adaptation is unknown, but fermentation performance increases with successive batch transfers.