A natural, biodegradable, anti-microbial plant pathogen control agent (BioPEP)

An increased global opposition to the use of harmful chemicals to control plant pathogens as well as a movement toward more natural and organic farming practices has led to a growing need for natural biocontrol agents. Researchers at Stellenbosch University have identified and formulated innovative natural compositions for use as highly effective biodegradable antifungal and antibacterial biocontrol agents, named biopepcides.

BioPEP is a biodegradable natural antimicrobial composition aimed at combating fungal plant pathogens, including two of the most destructive fungal diseases associated with grapevine decline, namely Black Foot Disease and Petri Disease.

There is currently only one chemical product on the market that claims to inhibit the growth of both bacterial and fungal pathogens, but it sometimes interferes with the development of the plant itself, especially in grapevine tissue culture.

Alternatives to chemical microbiocides, such as microbial biocontrol agents, provide an environmentally friendly alternative to protect produce, but in a changing environment, the efficacy of biological control is unpredictable and cannot guarantee protection against microbial pathogens.

The biocontrol agents of BioPEP have a broad spectrum of activity that can ensure the establishment of high-quality planting

material and also protect produce during postharvest storage. Production of these agents can be modified in order to target specific pathogens and organisms, and such production can be done cost effectively, with potential for large scale production.

The mechanism of action of these biocontrol agents ensures the low resistance potential of the pathogens being attacked.

• Agricultural markets, specifically for sterilisation in fresh fruit/ vegetable market
• Plant production industries such as viticulture and plant nurseries
• Floriculture and plant culture biotechnological industry
• Industries where chemical sterilisation procedures have failed and persistent microbial infections or microbial spores must be eliminated
• The academic research industry for the supply of fine chemicals.

The antimicrobial compositions of this innovation provide economical and effective biodegradable natural fungicide/microbicide alternatives or additives to other commercially available chemical fungicides and biocides. These antimicrobial compositions combat fungal and bacterial pathogens by:

• Eliminating fungal pathogens and bacteria from surfaces and solutions
• Preventing latent pathogen carry-over onto plant culture and nursery propagated plants
• Controlling and preventing pathogen infections in embryonic and young plants and plant materials
• The sterilisation of harvested fruits, vegetables and plant material during transport and storage to prevent post-harvest fungal and bacterial pathogens infections

The antimicrobial compositions:

• Are bio-degradable natural compounds leaving only breakdown products with nutritional value for plants in the environment
• Are cost effective with high levels of both crude and fine chemical grade production
• Exhibit multiple modes of action, thereby limiting the resistance potential of the biopepcide fungicides/microbicides to a minimum
• Have the potential to combat fungal plant pathogens to which no totally effective fungicide is available, such as Black Foot Disease (caused by Cylindrocarpon spp) and Petri Disease (caused by Phaeomoniella spp).

National phase patent applications in EPO, USA, South Africa amnd China based on PCT application publication  WO2013150394.

Both in vitro studies and  field trials have been completed. Laboratory scale production has been optimised and simplified purification protocols have been developed for both agricultural grade and fine chemical grade products.

Prof Marina Rautenbach - project coordinator

Dr Abré de Beer - production, crude preparations and field trials

Ms Anscha M. Troskie - laboratory trials, fine chemical production

Dr J Arnold Vosloo - production and crude preparation optimisation

The market reports on Antimicrobial Peptides, Antimicrobial Additives and Antimicrobial Coatings are all highly relevant to this technology and demonstrate a moderately to robust growing landscape with CAGR forecasts of ~5.3 to 11% in coming years, depending on the sector. These industries are highly fragmented and Europe and the US represent the leading regions due to high investment, accounting for 80% global share in 2016 (for antimicrobial peptides specifically). The global antimicrobial additives market is forecast for relatively stronger growth at CAGR 8.4% owing to the growing construction sector in the Asia Pacific region and rise of disposable income.