A genetic base of utilisation of maize grain as a valuable renewable raw material for bioethanol production

Abstract

Maize (Zea mays L.) is one of the most important cereal crops, and as such, one of the most significant naturally renewable carbohydrate raw materials for the production of energy and multitude of different products. Many studies have shown that the kernel composition and starch structure of maize are highly influenced by genetic background of the maize. Maize grain consists of approximately 70% of starch, which makes it a very suitable feedstock for the bioethanol production. This study was conducted with aim to understand how different genetic background affects bioethanol yield and other fermentation properties of the selected maize genotypes in the process of maize grain-based bioethanol production. Twenty seven maize hybrids, including genotypes of standard chemical composition as well as specialty maize hybrids such as popping, waxy, white kernel and red kernel hybrids, developed at the Maize Research Institute, Zemun Polje, were investigated in this study. The lowest bioethanol yield of 7.25% w/w obtained for hybrid ZP 611k after 48 h of fermentation and the highest by genotype ZP 434 (8.96% w/w). A very significant positive correlation was determined between kernel starch content and the bioethanol yield after 48h of fermentation, as well as volumetric productivity (48h) (r=0.67). Between bioethanol yield after 48h of fermentation and soft endosperm content in kernel of the investigated ZP maize hybrids a very significant positive correlation was assessed (r=0.66). Higher overall bioethanol yields have been obtained from genotypes containing higher starch and lower protein and lipid contents.