Prospects for increasing starch and sucrose yields for bioethanol production
Article first published online: 9 MAY 2008
© 2008 The Author. Journal compilation © 2008 Blackwell Publishing Ltd
The Plant Journal
Volume 54, Issue 4, pages 546–558, May 2008
How to Cite
Smith, A. M. (2008), Prospects for increasing starch and sucrose yields for bioethanol production. The Plant Journal, 54: 546–558. doi: 10.1111/j.1365-313X.2008.03468.x
- Issue published online: 9 MAY 2008
- Article first published online: 9 MAY 2008
- Received 8 November 2007; revised 14 February 2008; accepted 19 February 2008.
- crop plants;
In the short term, the production of bioethanol as a liquid transport fuel is almost entirely dependent on starch and sugars from existing food crops. The sustainability of this industry would be enhanced by increases in the yield of starch/sugar per hectare without further inputs into the crops concerned. Efforts to achieve increased yields of starch over the last three decades, in particular via manipulation of the enzyme ADPglucose pyrophosphorylase, have met with limited success. Other approaches have included manipulation of carbon partitioning within storage organs in favour of starch synthesis, and attempts to manipulate source–sink relationships. Some of the most promising results so far have come from manipulations that increase the availability of ATP for starch synthesis. Future options for achieving increased starch contents could include manipulation of starch degradation in organs in which starch turnover is occurring, and introduction of starch synthesis into the cytosol. Sucrose accumulation is much less well understood than starch synthesis, but recent results from research on sugar cane suggest that total sugar content can be greatly increased by conversion of sucrose into a non-metabolizable isomer. A better understanding of carbohydrate storage and turnover in relation to carbon assimilation and plant growth is required, both for improvement of starch and sugar crops and for attempts to increase biomass production in second-generation biofuel crops.