Biopesticides Produced by Fermentation

Biopesticides are regarded safer and more environmentally friendly than conventional chemical pesticides and can be used to manage pests, illnesses, and weeds as well as to promote plant development in agriculture.

What is Biopesticide?

Biopesticides are naturally occurring substances that are derived from living organisms including plants, bacteria, fungi, and viruses. Biopesticides are usually non-toxic to non-target organisms and biodegradable.

Types of biopesticides

• Microbial-based biopesticides: These are composed of living microorganisms, such as bacteria, fungi, or viruses, that act as natural enemies to pest insects.
• Plant-Incorporated Protectants (PIPs): PIPs are biopesticides that are produced by genetically modifying crops to express specific pest-controlling proteins. These proteins are naturally occurring in some plants and are toxic to certain pest insects.
• Biochemical-based biopesticides: These are composed of naturally occurring compounds with pesticidal properties, such as plant extracts. For examples, neem oil extracted from the neem tree, and pyrethrins derived from chrysanthemum flowers.
• Semiochemicals: Semiochemicals, such as pheromone and repellents, are natural substances that are utilized to thwart the mating habits of some insect pests.

Biopesticide Production by Fermentation

Fermentation is a metabolic process in which microorganisms are used to convert substrates into valuable products. Biopesticides can be produced by microbial fermentation that have the ability to biosynthesize and secrete toxic compounds that are lethal to pests. Microbial fermentation is controlled and easily scaled up to produce large quantities of biopesticides.

Solid-state fermentation (SSF) is a fermentation process used to produce biopesticides using agricultural wastes, grains, and plant residues as a solid substrate that provides a nutrient source for the microorganism hosts. The microorganisms secrete enzymes that break down the substrate into monosaccharides that can be used as a source of energy, consuming energy to produce the desired product.

Microorganisms Used in Production of Biopesticides

Several microorganisms can produce biopesticides by fermentation and they can be bacteria, fungi or viruses that are naturally occurring or genetically modified to produce specific pest-control compounds or used as pesticides themselves. These microorganisms include Bacillus thuringiensis, Beauveria bassiana, and Granulovirus. These microorganisms are grown on suitable substrates by solid-state fermentation or liquid fermentation techniques.

• Bacillus thuringiensis: Bacillus thuringiensis is a bacteria that produces a protein that is toxic to a wide range of insect pests. The protein, known as Cry toxin, is produced during the sporulation phase of bacterial growth.
• Beauveria bassiana: Beauveria bassiana is a naturally occurring fungus that can be used as a biopesticide. The fungus parasitizes a wide range of insect pests, including whiteflies, aphids, and thrips.
• Granulovirus: Granulovirus is a virus that is used as a biopesticide to control caterpillar pests. The virus infects the target insect and causes it to stop feeding and eventually die.

Fermentation Techniques in Production of Biopesticides

Fermentation techniques used to produce biopesticides include submerged fermentation, solid-state fermentation, and mixed fermentation using liquid substrates, solid substrates, and liquid and solid substrates, respectively. Fermentation techniques provide a reliable and effective method for the production of bioactive compounds from natural sources.

• Selection of an appropriate microbial strain. A large number of strains are screened to determine the most effective strain for the production of the desired bioactive compound. Control the growth conditions of the strains such as medium, temperature, pH and aeration.
• Production of bioactive compounds. Microorganisms consume nutrients in the medium to produce the desired bioactive compounds, which can be extracted from the fermentation broth by various methods such as filtration, centrifugation and solvent extraction.
• Purification of desired compounds. After extraction the compounds are further processed to remove impurities by high performance liquid chromatography (HPLC) or gas chromatography (GC).
• Formulation of target products. The compounds are combined with other components such as adjuvants, surfactants and carriers to improve their stability, efficacy and handling properties.

Applications of biopesticides

Biopesticides have a variety of applications in agriculture, horticulture, forestry and public health. They can be used to control pests in crops, ornamentals, turf and forests, as well as to kill mosquitoes that transmit diseases such as malaria and dengue fever.

The production of biopesticides by fermentation is a promising and sustainable alternative to conventional pesticides that reduces adverse environmental and human health impacts and provides a controlled and efficient method of producing large quantities of biopesticides. In addition, biopesticides have a lower risk of developing resistance in pests, making them a long-term pest control solution. With further research and development, biopesticides have the potential to become a more widely used tool in pest management.