Conversion of non-food based feedstocks to bioethanol and other products can be broadly classified into chemical and biological processes. Further, biological conversion of biomass can be through direct or indirect fermentation. Bioethanol can be produced through direct fermentation of the biomass via hydrolysis-fermentation and through indirect fermentation via syngas fermentation. In this article, ethanol production through hydrolysis-fermentation is briefly discussed followed by a detailed review of syngas fermentation process an indirect biomass conversion process to produce bioethanol. Discussion on thermochemical conversion processes can be found elsewhere and is out of scope of this review article