What are the advantages and disadvantages of solid culture fermentation, liquid fermentation and immobilized cell fermentation?

What are the advantages and disadvantages of solid culture fermentation, submerged fermentation and immobilized cell fermentation? What are the advantages and disadvantages of solid culture and liquid culture? The advantages of solid culture are simple operation, low equipment investment, low production cost, low requirements for the quality of operators and almost no sewage. The disadvantages are low production efficiency, large labor, difficult automation, uneven fermentation, extensive technology and large floor space, which is suitable for low value-added products.

The advantages of liquid culture are submerged culture, high production efficiency, easy automatic control, and accurate control of the process by various means. However, the disadvantages are large equipment investment, strict sterilization, complicated operation, high quality requirements for operators and large amount of fermented sewage, which is suitable for high added value and large-scale production.

Advantages and disadvantages of solid fermentation and liquid fermentation solid fermentation

Advantages of solid fermentation:

1. The culture medium is simple, such as grain, wheat bran, wheat straw, bulk grain or agricultural products. The cost of fermentation raw materials is economical.

2. Substrate pretreatment is less than liquid fermentation, such as simply adding water to moisten the substrate, or simply grinding the substrate to increase the contact area, without special equipment, which can be carried out by ordinary families.

3. Because taking water can reduce the pollution of miscellaneous bacteria, this low sterilization step can be used for fermentation and is suitable for low-tech areas.

4. It can produce special products, such as the red pigment produced by monascus is ten times that produced by liquid fermentation, and the glucosidase produced by Aspergillus in solid fermentation is more heat-resistant than that produced by liquid fermentation.

5. Solid fermentation is equivalent to using a relatively high culture medium, which can be fermented in a smaller reactor, and the output per unit volume is higher than that of liquid.

6. Downstream recovery and purification processes and waste treatment are usually simplified or simple, and the whole substrate is often used. If it is used as a new feed, it does not need to be recycled and purified, and there is no waste problem.

7. Solid fermentation can produce special flavor and improve the nutritional value of food. For example, Tianpei can be used as a substitute for meat, and its amino acids and fatty acids are easily digested and absorbed by the human body.

Disadvantages of solid fermentation:

1. is limited to microorganisms growing in low humidity, so the possible processes and products are limited, and it is generally suitable for fungi.

2. When fermenting in a dense environment, there are often problems in removing metabolic heat, especially in large-scale production, which often limits its large-scale production capacity.

3. It is difficult to detect various parameters in solid state, especially the probe of liquid fermentation is not suitable for solid state fermentation, pH value, humidity, substrate concentration are not easy to adjust and control, biomass is not easy to determine, fermentation conditions in different batches are inconsistent, and the reproducibility is poor.

4. Mixing is not easy to transfer mass, so the addition of substances during fermentation is not uniform.

5. Because it is not easy to detect, from the perspective of fermentation engineering, a lot of work is only qualitative or observational, so it is difficult to design a reactor, and it is difficult to quantify production or design a reasonable fermentation process.

6. Solid fermentation takes a long time, and the yield and productivity are often lower than that of liquid fermentation.

7. Because of its high viscosity, the extracted products are usually difficult to concentrate in large quantities.

Advantages of fungi in solid fermentation

1. It can grow at low water content (the activity of adapting to water is 0.7-0.93-0.98), while the activity of adapting to water by bacterial yeast is more than 0.99.

2. Bacteria are generally difficult to grow at low pH value, while fungi grow well at low pH value ... and the pH value of solid culture medium is difficult to control, so this characteristic of fungi is beneficial to solid fermentation.

3. Solid substrates are usually macromolecular compounds, such as starch, cellulose, hemicellulose, pectin, lignin, protein, lipids, etc. Fungi can often secrete these extracellular enzymes and use the surrounding culture substrates as carbon and nitrogen sources.

4. If fungi have sporulation characteristics, they are easy to store and inoculate, and personnel can inoculate spores without too much training.

5. The growth mode of mycelium is better than that of single cell. The top of the mycelium extends and branches to produce a new mycelium end, which can quickly cover the surface of the solid substrate and effectively use the substrate.

6. If hyphae are separated, substances can be transmitted through pores, and the pores will be automatically closed in case of danger to avoid the loss of cytoplasm; If there is no partition, the substances in the cytoplasm are quickly transferred, which makes the colonies multiply rapidly.

7. The growth of mycelium has a strong force to penetrate into the solid medium, forming a high mechanical pressure, and it is easy to penetrate into the solid medium with the hydrolase secreted by the tip.

Liquid fermentation

superiority

Shorten dough fermentation time and improve production efficiency; Automatic and continuous production can be realized from raw and auxiliary materials processing to finished product packaging; Extend the shelf life of bread and delay the aging speed; Shorten fermentation time.

What are the advantages of immobilized cell fermentation?

1, compared with free cells.

Compared with free cell fermentation, immobilized cell fermentation has the following advantages:

(1) Immobilized cells can transform microbial fermentation into continuous enzymatic reaction.

(2) Higher cell concentration can be obtained;

(3) cells can be reused;

(4) At high dilution rate, elution will not occur;

(5) high yield per unit volume;

(6) improving genetic stability;

(7) Cells will not be affected by shearing effect.

(8) The content of bacteria in the fermentation broth is low, which is beneficial to the separation and purification of products.

2. Compared with immobilized enzyme,

Compared with immobilized enzymes, immobilized cells have the following advantages:

(1) eliminates the process of extracting enzyme from broken cells.

(2) The stability of intracellular enzyme is high, and the loss of enzyme activity is less after whole cell immobilization.

(3) The preparation cost of immobilized cells is lower than that of immobilized enzymes.

(4) No coenzyme regeneration is needed.

Second, the shortcomings of immobilized cells

Although immobilized cells have many advantages mentioned above, they also have some disadvantages, as follows:

1, only intracellular enzymes can be used;

2. Cell membrane, cell wall and carrier all have diffusion limiting effects;

3. The pore size formed by the carrier affects the permeability of polymer matrix;

4. There may be side effects.

What is immobilized cell fermentation broth? Immobilized cell fermentation refers to the method of locating free cells in a limited space by physical or chemical means and keeping their catalytic activity for reuse. The fermentation broth produced by immobilized cells is called immobilized cell fermentation broth. The supernatant after centrifugation is not because it is not produced by immobilized cell fermentation. Of course, if we can centrifuge the whole fermentation process, it is also considered. But what you said is definitely not the case.

What are the advantages of immobilized yeast cells in producing ethanol compared with free cells? 1. The initial fermentation time of immobilized yeast is shorter than that of free yeast, and the fermentation speed is faster than that of free yeast. 2. During the fermentation time of 12 days, the alcohol content produced by immobilized yeast was nearly 50% higher than that of free yeast. 3. The acidity of the fermentation broth of immobilized yeast is less than that of free yeast, and the acidity of the fermentation broth is relatively stable, so it has good resistance to acid-producing bacteria. 4. Immobilized yeast fermentation is more thorough and takes less time than free yeast fermentation.

Advantages and disadvantages of solid fermentation and liquid fermentation. What are the advantages and disadvantages of "solid fermentation" and "liquid fermentation"? 1. Solid state fermentation:

Advantages:

Low water activity, high water insolubility of substrate, easy growth of microorganisms, high enzyme activity and rich enzyme system;

The fermentation process is extensive, and strict aseptic conditions are not needed;

The device has the advantages of simple structure, low investment, low energy consumption and easy operation;

Simple post-treatment, less pollution, and basically no wastewater discharge.

Disadvantages:

Limited to microorganisms with low water activity, there are few choices.

The fermentation speed is slow and the period is long.

The composition of natural raw materials is complex and sometimes changes, which affects the yield and quality.

Process parameters are difficult to detect and control.

Less products, more labor and high strength.

Second, liquid fermentation.

Advantages:

quick

low cost

high-production

Disadvantages:

Because of the fast production speed of alcohol, there are few or no other ingredients, so it is necessary to add essence artificially to supplement other ingredients.

Solid-state fermentation is a fermentation mode of microorganisms on solid substrates with little or no free water. Gas, liquid and solid coexist in solid matrix, that is, porous solid matrix contains water and water-insoluble substances.

The production technology of liquor and aged vinegar is typical solid-state fermentation, which converts sugar in grain into alcohol and then into vinegar. Relative liquid fermentation, such as glutamic acid fermentation in monosodium glutamate production and xanthan gum production fermentation.

Liquid fermentation refers to the fact that the raw materials of wine-making are in liquid state and submerged, so it is called liquid fermentation.

Why is the alcohol fermentation broth of immobilized cells clearer? Immobilized cell fermentation technology has many outstanding advantages: because it greatly improves the cell concentration and enhances the resistance of bacteria to external conditions such as temperature and pH; Shorten the fermentation period and improve the biotransformation rate per unit volume of the reactor; Moreover, because the cells are fixed, the cell loss is reduced, and the cells can be reused for a long time, which is beneficial to product separation. This provides convenience for continuous large-scale fermentation.

At present, immobilized cell technology has been widely used in food industry, environmental protection, energy development and other fields.

The immobilization of alcohol yeast cells mostly adopts embedding methods such as sodium alginate and polyvinyl alcohol, but there are some shortcomings such as high cost, complicated immobilization process, damage to cells and softening of carriers.

It is the development direction of immobilization technology to explore new immobilization carriers and methods and create an environment more suitable for cell growth and metabolism. Various natural materials, such as fruit pieces, bran and delignified cellulose residues, have been successfully used as immobilized carriers in food-related industries such as wine making and whey fermentation.

It is beneficial to yeast adsorption and its adsorption by using the natural cell fiber gap in sugarcane stem block and the adsorption of cellulose itself.

According to the characteristics of internal growth, immobilized yeast was prepared and used to ferment sugarcane juice to produce alcohol.

Why do immobilized yeast cells need anaerobic (1) microbial laboratory culture? The key is to prevent contamination by miscellaneous bacteria, so the whole process should be strictly sterile.

(2) Yeast produces alcohol through anaerobic respiration. When making wine, yeast comes from wild yeast attached to grape skins.

(3) Among the four microorganisms, yeast, Acetobacter, Penicillium and Mucor, only yeast is facultative anaerobic (it can breathe both aerobic and anaerobic). Therefore, in order to separate pure yeast, anaerobic environment can be directly provided for separation.

(4) Preparation of immobilized yeast cells, commonly used embedding material is sodium alginate, and the application method is shown in Figure ③.

(5) Gel chromatography is used to separate protein according to its relative molecular weight. Because the relative molecular weight is large, it cannot enter the gel channel, so it moves fast. Firstly, the enzyme was separated, and then the enzyme was separated by electrophoresis. The factors that affect the electrophoresis speed of enzyme include the amount of charge, the nature of charge, voltage, the size and shape of molecules, etc.

So the answer is: (1) sterile.

(2) Wild yeast attached to grape skin

(3) Anaerobic

(4) Sodium alginate ③

(5) The relative mass, charged quantity, charged property, voltage, size and shape of the molecule, etc.