Optimization of the technology for solid-state fermentation of sweet sorghum stems to produce fuel ethanol

In order to explore a new-style biological energy-source, the technological parameters for production of fuel ethanol with sweet sorghum stems were investigated. On the basis of single-factor experiment, the orthogonal experiment was conducted for the optimization of technological parameters. The results show that the fermentation temperature, pH value and nutrition salt make great impact on ethanol yields, initial rate of fermentation and fermentation period of solid-state fermentation of sweet sorghum stems. While the types of yeast and filling-coefficient only affected the ethanol yields and initial rate of fermentation, but had no impact on the period of fermentation. Under the condition of filling-coefficient 80%, pH value 3.5, the Danbaoli alcohol yeast and the nutrition salt 2, the optimized parameters were that the fermentation temperature, dosage of nutrition salt and inoculation dosage were 22℃ or 25℃, 0.02% and 0.08%,respectively.According the above mentioned optimum conditions for producing fuel ethanol, the highest alcohol degree was 6.6%(V/V). The research provides a scientific basis for fuel ethanol development.