Is the fermentation of biodiesel belongs to the biological fermentation ? How to chose the suitable fermenter?

Biodiesel is a kind of renewable energy through the conversion of biomass raw materials, as a substitute for traditional diesel, because of its environmental protection, low emission characteristics, has become one of the focus of the global energy industry research and development. Biodiesel can be produced in a variety of ways, the most common of which is through the conversion of vegetable oils or animal fats. However, in recent years, with the progress of biological fermentation technology, more and more studies have begun to explore the use of microbial fermentation to produce biodiesel. This paper will discuss whether the fermentation of biodiesel belongs to biological fermentation and discuss the influence of fermenter selection on biodiesel production.

I. Overview of biodiesel production

Biodiesel is extracted mainly from vegetable oils, animal oils, or waste oils through "Transesterification," in which vegetable oils and animal fats serve as the main sources of Triglycerides. These raw materials react with alcohols (such as methanol and ethanol) to catalyze the formation of fatty acid methyl ester or ethyl ester, and then produce biodiesel.

Biodiesel production is generally divided into the following steps:

Raw material preparation and oil extraction

First, the oil needs to be extracted from plant seeds or animal fats. Common plant raw materials include soybeans, rapeseed, palm, etc. The oil is usually extracted by pressing or solvent extraction.

transesterification

Triglycerides in vegetable oils are chemically reacted with methanol or ethanol to produce fatty acid methyl ester (FAME) and glycerol. The reaction requires the use of a catalyst (usually sodium hydroxide or potassium hydroxide) to speed up the reaction process.

Product separation and purification

After transesterification, the products will contain unreacted raw materials, catalysts, glycerol and other impurities. By washing, separation, drying and other methods to remove impurities, the final biodiesel.

However, the production of biodiesel is not limited to the chemical synthesis process. With the in-depth research of microbial fermentation technology, the production method of fatty acid methyl ester or biodiesel using microbial fermentation has begun to attract attention. This way is different from traditional chemical reactions, and is achieved through the metabolic activity of microorganisms.

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II, microbial fermentation and biodiesel production

In microbial fermentation, specific microorganisms (such as yeast, bacteria, or algae) produce fatty acids or fatty acid methyl esters through a biosynthetic pathway. This process is different from traditional biodiesel production through vegetable oil conversion, because it does not rely on external oil raw materials, but directly synthesizes fatty acids and other products through microbial metabolism.

The process of microbial fermentation to produce biodiesel usually involves the following steps:

Microbial selection and culture

Microorganisms such as certain yeast, bacteria, algae, etc., can accumulate large amounts of oil under the right conditions. For example, certain yeasts (such as Yarrowia lipolytica) synthesize large amounts of oils when there is an excess of carbon sources, which can be produced by conversion reactions to biodiesel.

Fermentation process

Microorganisms grow and metabolize in fermenters, accumulating fatty acids or fatty acid methyl esters. In order to increase the production of biodiesel, it is usually necessary to optimize the fermentation conditions, such as carbon source, nitrogen source, temperature, pH value, dissolved oxygen, etc.

Oil extraction and transformation

Once the microbes have accumulated enough oil, it is usually necessary to extract the oil from inside the cells and then convert it into biodiesel through a transesterification reaction. This process is similar to the traditional vegetable oil conversion process.

Compared with the chemical transesterification reaction, the advantage of microbial fermentation production of biodiesel is that it does not rely on external oil raw materials, and can use waste or low-cost raw materials (such as discarded plant residues, sugar waste, etc.) as the fermentation substrate, which has a certain economy and environmental protection.

III, is fermentation biological fermentation?

So, can the fermentation process of biodiesel be called "biological fermentation"? "Biological fermentation" usually refers to the process of transforming raw materials to produce certain products through the metabolic activities of microorganisms, such as fermenting alcohol, acids, antibiotics, etc. According to this definition, the process of using microbial fermentation to produce biodiesel can indeed be regarded as a "biological fermentation" process.

However, unlike the traditional fermentation industry (such as alcohol fermentation, acetic acid fermentation, etc.), the production of biodiesel does not rely on metabolic products produced by biological fermentation (such as ethanol, lactic acid, etc.), but fatty acids and fatty acid methyl esters synthesized by microorganisms. Therefore, although microorganisms synthesize fats during fermentation, this process is often referred to as "microbial oil synthesis" rather than "biological fermentation" in the traditional sense.

In summary, biodiesel production does not belong to traditional biological fermentation under chemical methods, but is an alternative energy source formed in the process of microbial oil synthesis. The method of oil synthesis by microbial fermentation can be regarded as an innovative application of biological fermentation.

IV, the choice of fermenter

In the process of biodiesel production, the choice of fermenter is very important, whether it is traditional chemical transesterification or microbial fermentation. Fermenter not only affects the growth and metabolic efficiency of microorganisms, but also directly affects the yield and quality of biodiesel. Choosing the right fermenter is the key to ensuring efficient production.

Stirring fermenter

For microbial fermentation processes, stirring fermenters are usually used. Such fermenters maintain a uniform solution through mechanical agitation or gas agitation (such as air or oxygen), ensuring that microorganisms have adequate access to nutrients and that oxygen is sufficiently dissolved. This fermenter is suitable for fermentation processes requiring higher dissolved oxygen.

Airlift fermenter

The airlift fermenter is widely used in microbial fermentation which requires higher gas volume and lower shear force by stirring the culture liquid through the upward flow of gas. For some microorganisms that are more sensitive to shear forces, airlift fermenters can provide a milder growth environment.

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Continuous fermenter and batch fermenter

Continuous fermenter and batch fermenter are two common fermentation modes. Batch fermentation is suitable for small-scale production and can complete a fermentation process in a short time. Continuous fermentation is suitable for large-scale production, which can continuously add raw materials and continuously extract products, thereby improving production efficiency.

External circulating fermenter

The outer cycle fermenter is suitable for large-scale industrial production, and its design can effectively control the temperature, pH, dissolved oxygen and other parameters inside the fermenter. The stability and uniformity of the medium can be ensured by circulating the medium through an external pipe.

When choosing a fermenter, it is necessary to consider several factors such as the scale of fermentation, the level of dissolved oxygen required, reaction conditions (such as temperature, pH), and the economics of operation. For biodiesel production by microbial fermentation, optimization of fermenter design and operation conditions can significantly improve the yield and production efficiency.

V,conclusion

Whether the fermentation production of biodiesel is "biological fermentation" depends to a certain extent on the breadth of its definition. Traditional biological fermentation mostly refers to the process of producing certain products through microbial metabolism, while microbial fermentation production of biodiesel is more focused on the synthesis of oil through microorganisms, and then converted into biodiesel. Although there are certain differences, from a technical and biological point of view, microbial fermentation to produce biodiesel can be regarded as a new application of biological fermentation.

In addition, choosing the right fermenter is crucial to the production of biodiesel. Different types of fermenters can provide optimal growth conditions according to different production requirements, provide support for microbial fermentation, and ultimately improve the yield and quality of biodiesel. With the continuous progress of technology, the fermentation production method of biodiesel is expected to be more widely used in the future and become an important part of the global renewable energy field.

On the other hand, when choosing a bioreactor fermenter, it is necessary to find a regular manufacturer with good reputation and strength, so as to ensure the quality of the product. Jiangsu Mike Biotechnology Co., Ltd. was established in 2008, is a focus on biological fermentation equipment research and development, production and sales of high-tech enterprises. Our company has a pilot fermentation platform, which is integrated with intelligence and automation, and has built a mature fermentation system, which can realize the optimization of pilot fermentation process, commissioning development of all process processes from pilot fermentation production to fermentation product separation and purification, and set up a doctor workstation and a modern laboratory.

Our company has a standardized production plant, with complete sets of equipment and tools required for installation, mainly including a variety of machine tools, automatic argon arc welding machine, automatic polishing machine, automatic cutting machine and flaw detection machine and other more than 60 sets of production and testing equipment, the production process all realize modern standard operation, to provide customers with more professional quality and technical support.