Two-step pH regulation method for producing ethanol through fermentation of synthesis gas

Abstract

The invention discloses a two-step pH regulation method for producing ethanol by fermentation of synthesis gas, which is characterized by comprising the following steps: strictly deoxidizing a culture medium in an anaerobic fermentation bottle, and inoculating acetic acid-producing mixed strains into the strictly deoxidized anaerobic fermentation bottle containing the culture medium according to a certain volume ratio; setting the pH value of a culture solution in an anaerobic fermentation bottle according to the requirement of the acetic acid-producing mixed bacteria on pH in rapid growth, and adjusting and keeping the constant pH value through a pH value real-time measurement and feedback device so as to promote the growth of the acetic acid-producing bacteria and enable the acetic acid-producing bacteria to enter a rapid biomass enrichment stage; continuously introducing synthesis gas containing CO, CO2 and H2 into an anaerobic fermentation bottle as a gas substrate for fermentation, regulating the pH value of a culture solution in the anaerobic fermentation bottle to a proper range and keeping the pH value constant according to the pH value requirement of the strain for rapid ethanol production after the strain grows to a stable phase and is enriched with enough biomass, so that acetic acid-producing mixed bacteria enter a rapid ethanol production stage, and the method can be widely applied to the fields of energy conservation and emission reduction, environmental improvement, clean energy and the like.

Description

technical field [0001] The invention relates to a method for ethanol production by gas fermentation, in particular to a two-step method for pH regulation and control of synthesis gas fermentation ethanol production performance. Background technique [0002] Syngas is produced in the form of CO, CO 2 、H 2 The mixed gas as the main component is widely produced in fossil fuel combustion, agricultural and forestry waste gasification, and industrial waste gas from steel plants. If it is not utilized, it will not only cause a lot of energy waste, but also cause a series of ecological problems. Environmental issues. Take CO, CO 2 、H 2 The main synthetic gas can be converted into liquid fuel (such as ethanol, etc.) by using microbial fermentation technology. The process conditions of pyrolysis gas fermentation are easy to realize and its energy consumption is low, the acquisition of raw materials is relatively easy, and its distribution is also very wide; at the same time, the ...

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Problems solved by technology

[0004] The pH adjustment method currently used is to adjust before the strain inoculation, so that the culture solution reaches the pH range most suitable for the growth of the strain. However, during the growth and reproduction of bacteria, organic acids are produced. With continuous accumulation, the pH value of the solution is also decreasing, coupled with the impact of continuous gas supply, the acid-base environment at this time has entered a range that is not suitable for bacterial growth, resulting in no further increase or even a decline in the bacterial population density. The lower bacterial population density also reduces its ability to absorb and utilize gas, resulting in lower alcohol production

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