Breeding Of Bacteria For Corn Alcohol Stillage Treatment

In view of the present situation of corn alcohol stillage in China, a new technological process in which distillers' grains can be reused has been put forward in our laboratory. First, distillers' grains are directly cooled instead of being separated. Then high quality bacteria are transferred to them so aerobic ferment process begins. Microbial protein contents increase and organic matter is significantly biodegraded during this process. Finally, the reactants are separated. The stillage filtrate can be directly reused to mix corn to produce alcohol and the residues can be used as protein feed. It is a kind of clean process.In this study, breeding bacteria is the key step. Through aerobic ferment and ultraviolet mutualism, many factors were investigated such as formation and regeneration of protoplasm, ultraviolet mutalism, growth of the mutant as well as optimal conditions of aerobic ferment. During the process, breeding high quality bacteria, ultraviolet mutagism of protoplasm, batch ferment and semi-continuous ferment were conducted and the following results were concluded: high-production protein bacteria were gained by ultraviolet mutalism. After 40h when the mutants were introduced into the alcohol stillage, the removal efficiency of COD increased from 60 to 75 percent, and the crude protein contents increased from 31 to 44 percent, and pH increased from 3-4 to 5-6, compared with the original bacteria.Due to its low investment and high environmental and economic benefits, this new process will have a bright future in the field of alcohol producing. The thesis has included the key technology of the new process and thus the results will play an important role in the development and application of the technology in the future.