Rhamnolipids as a natural product have numerous applications in agriculture and farming. They are environmentally and ecologically safe. As a surfactant they can function as a wetting agent, sticker, and dispersal agent for the application of agricultural fungicides and pesticides. In very low dilutions they are effective as a fungicide and bactericide for certain agricultural pests. As a wetting fungicide they will prove useful in protecting foods from spoilage in storage.
Rhamnolipids as a Pesticide Surfactant
Rhamnolipids are being used to replace existing surfactants in pesticides. Rhamnolipid biosurfactants can operate in extreme conditions, are non-toxic, and are themselves biodegradable. In pesticide applications they serve as wetting agents, solubiliziers, stabilizers, emulsifiers, and foaming agents. Rhamnolipids help distribute the active ingredients uniformly within the pesticide formulation during application. Rhamnolipids can be formulated to match the attributes of the desired application.
Rhamnolipids as a Fungicide and Oomycota Inhibitors
Rhamnolipids have been demonstrated to lysis fungal zoospores on contact. The rhamnolipids break the plasma membrane of the zoospores, which do not have a cell wall. Rhamnolipids are therefore a method of controlling the spreading of a number of a number of fungal plant pathogens such as the powdery mildews including Erysiphe necator and Blumeria graminis
Rhamnolipids have also been demonstrated to inhibit the growth and motility of oomycota zoospores. These fungus-like organisms represent a large group of problematic plant pathogens including those commonly known as downy mildew (Peronosporaceae) and root rots such as Phytophthora and Pythium.
In hydroponics, the common watering system can spread many of these diseases. The inclusion of a small amount of rhamnolipids in the water supply can inhibit the spread of these diseases while at the same time emulsified or chelating nutrients and facilitating the update of nutrients into the plants.
Because of the US Environmental Protection Agency (EPA) approval, rhamnolipids can be used as a liquid contact biofungicide for horticulture including turf, landscaping, and agriculture.
Rhamnolipids as an Antibiotic
Rhamnolipids have been shown to control some gram-positive bacteria. Rhamnolipid producing bacteria have used rhamnolipids to suppress the growth of competing bacteria.
Rhamnolipids have also been found to increase the susceptibility of gram-positive bacteria to other antibiotics.
Rhamnolipids as the Natural “Green” Pesticide
Pesticides have a long history of being extremely toxic, persistent, and harmful to the environment. Major pollution problems have been associated with the production and use of pesticides. Metabolic products and degradation residuals have proven to be long-term environmental pollutants, especially when the compounds contained toxic metals, chorine, and fluorine. Most of these have been banned or are limited to very restricted use.
In contrast, rhamnolipids are a naturally occurring compounds found naturally in soils, water, oil spills, and on plants. They are produced and purified using natural “green” technology. Although they are stable over a wide range of temperatures and pressures, they are naturally biodegradable. Rhamnolipids contain only the common elements of carbon, hydrogen, and oxygen. During biodegradation rhamnolipids are broken down into rhamnose sugars and common fatty acids that are easily metabolized.