Ⅰ.Soybean inoculants are generally used in a wide range of applications
1. Agriculture
- Seed treatment: The inoculant is applied directly to soybean seeds, through seed mixing or coating, to make rhizobacteria adhere to the seed surface, to promote the formation of rhizomes and nitrogen fixation.
- Soil application: The inoculant is applied to the soil at the time of sowing to help the soybean root system form rhizomes quickly and increase nitrogen supply.
The inoculant has been shown to significantly boost nodulation rate, stem weight and seed yield in soybeans, as well as enhancing the plant's tolerance to abiotic stresses such as drought.
- Sustainable agriculture: as an alternative to chemical fertilisers, it reduces the use of nitrogen fertilisers and lowers production costs, while improving soil health.
2. Biological control: Used in combination with mycorrhizal fungi, Bacillus or other beneficial microorganisms, it can enhance the plant's ability to control pests and diseases.
3. Ecological restoration: used in the ecological restoration of degraded soil, improving soil fertility through nitrogen fixation.
4. Feed and biofuel: in the production of soybeans as feed or biofuel raw materials, the inoculant can improve its nutritional value and yield.
Ⅱ.What parameters to look for in a bioreactor
When using a bioreactor to cultivate slow-growing rhizobacteria, it is essential to strictly control the fermentation conditions to achieve a high-density culture.
Preparation of the fermenter should be carried out with a high-quality stainless steel bioreactor equipped with an automatic control system for temperature, pH, stirring rate and dissolved oxygen regulation.
The fermentation conditions are as follows:Temperature: 28°C.Dissolved oxygen: not less than 85%.
The stirring speed should be a minimum of 400 rpm.
The pH should be set at 6.8.
Replenishment strategy: constant velocity flow addition replenishment, the ratio of carbon and nitrogen sources in the replenishment solution is 3:2, the flow rate is 1 ml/min, and the replenishment time is 10-12 hours.
The fermentation process was then allowed to incubate for 48-60 hours, enabling the bacteria to enter the logarithmic growth phase.
Ⅲ.Matters need attention
1. Contamination control:
The following measures are to be implemented:
- Sterility testing of biosafety cabinets and operator gloves is to be conducted prior to operation.
Furthermore, regular sterility testing of cultures is imperative, especially during passaging and inoculation.
2. Parameter optimisation:
This involves adjusting the medium formulation and fermentation parameters according to the characteristics of the specific strain being cultivated.
Furthermore, regular monitoring of pH, dissolved oxygen and temperature is required to ensure stability.
3. Equipment maintenance:
This should include regular cleaning and maintenance of the bioreactor to avoid residues affecting subsequent cultures.
It is also crucial to ensure that the equipment is well grounded to avert electrical safety hazards.
4. Storage conditions:
Cultured inoculants should be stored at low temperature (15-28°C) and the packaging material should be well ventilated.
