Liquid strains refer to edible fungi strains in liquid form produced through deep culture (liquid fermentation) technology using liquid culture media in biological fermentation tanks. It is mainly distinguished from solid strains based on the morphology of the strains, which has the following three major advantages: 1. Low cost. Liquid strains take up little space, use low-cost raw materials, and require less labor, so their production costs can be significantly reduced. 2. Grows fast. Generally, the cultivation time of strains in Erlenmeyer flasks and fermenters is 7 to 10 days, which greatly shortens the strain production cycle. 3. Good quality. The liquid strains have high purity, strong vitality, and consistent bacterial ages. The mycelium in the cultivation bottle has good uniformity, the mushrooms are neatly produced, and the product quality is good. In production applications, the main advantage is low cost. The survey results show that the direct production cost of liquid mushroom strains is only 40% of that of solid strains. In an Enoki mushroom factory that fully uses liquid strains, the cost of strains accounts for only 2% of the total cost.
However, liquid strains have higher requirements on equipment, environment, cultivation materials, etc. The main equipment required in the production process of liquid strains is fermentation tanks, liquid strain inoculation machines, fermentation tank supporting sterilizers, air compressors and air purification systems, etc. The equipment requirements are high and the one-time investment is large. In order to minimize the contamination rate, the clean area space needs to be purified to level 10,000, among which the inoculation machine and the fermentation tank inoculation area need to be purified to level 100. The cultivation material needs to be thoroughly sterilized, with appropriate moisture, temperature and pH, so that the liquid bacteria can be quickly sealed within 2 to 3 days. At the same time, the production process of edible fungi liquid strains is an interdisciplinary subject that combines edible fungi and industrial fermentation technology. It has high requirements for technical personnel. They not only need to master the basic knowledge of edible fungus cultivation, but also need to understand and master the fermentation system, Basic knowledge of machine equipment systems. Liquid strains are not easy to preserve and must be put into use immediately after production. Generally, the interruption time of purified air during the factory production process cannot exceed 3 hours. After that, they will be scrapped. In view of this, liquid strains are more suitable for large-scale, annual, and factory-based production enterprises of edible fungi.