We provide an overview of the current status of bioenergy development, focusing on first- and second-generation liquid biofuels, considering drivers of growth and risks that have raised concerns over recent years. We also describe the main areas where biotechnologies are being, or can be, applied for production of first- and second-generation biofuels as well as microalgal biodiesel and biogas. Greatest attention is paid to second-generation biofuels in the review because of the large expectations they have created and because of the significant role that biotechnology applications are likely to play in their development. We close with some specific considerations regarding applying biotechnologies for bioenergy development in developing countries. (C) 2010 Elsevier Ltd. All rights reserved.