A study reveals the potential for agriculture to reduce its reliance on nonrenewable fertilizers.

 A study reveals the potential for agriculture to reduce its reliance on nonrenewable fertilizers.

An enzyme that can aid in the release of phosphorus from its organic forms has been identified in a study published in the leading science journal PNAS by the University of Sheffield's Institute for Sustainable Food.

Inorganic rock phosphate sources are becoming increasingly expensive.

All organisms on Earth, plants and animals alike, require phosphorus for healthy growth and development; however, the continued use of non-renewable phosphorus chemical fertilizers in agriculture endangers crop yields and the sustainability of our global food production systems. Agriculture is the largest consumer of nonrenewable phosphorus, so its scarcity has serious consequences for global food security, biodiversity, and climate regulation.

Because the availability of organic phosphate nutrients in the environment is often insufficient to limit natural plant and algae growth, the most basic form of phosphorus used in fertilizers is non-renewable inorganic phosphate.

The majority of total phosphorus in the ocean and soil exists in complex organic forms that require enzymes known as phosphatases to release the phosphate so that plants and algae can use it as a nutrient.

PafA, a unique bacterial phosphatase abundant in the environment discovered by researchers at the University's Institute for Sustainable Food, can efficiently release the phosphate used in fertilizers from its organic forms.

The study used a Flavobacterium model to examine the PafA function in vivo and discovered that it can rapidly mineralize naturally occurring organic phosphate regardless of phosphate level, a process that was found to be inhibited by other common enzymes such as PhoX and PhoA phosphatases, particularly if residual levels of phosphate were present.

According to Dr. Ian Lidbury of the University of Sheffield's Institute for Sustainable Food and the Arthur Willis Environmental Research Centre,

"the accumulation of phosphate can inhibit enzyme activity in the most common phosphatases, but PafA is unique in that its function does not suffer when phosphate accumulates."

"As there is a high occurrence and diversity of PafA in the environment, both on land and aquatic environments, this makes it a valuable overlooked resource for finding ways to help plants and animals more efficiently capture essential nutrients, and will be crucial to help us reducing our reliance on—and the damage caused by rapidly using up—the world's limited stocks of non-renewable chemical phosphorus fertilizers." 

"Our further research will investigate how PafA functions, as Flavobacterium forms appear to be particularly active compared to others. So understanding this is crucial for us to be able to engineer optimized enzymes for use in agriculture." 

 

 The team is now investigating what makes some forms of PafA more active than others, with the goal of developing an enzyme that can be used to promote sustainable agriculture by providing more readily available organic sources of phosphorus for plants, with the potential to be introduced into animal feeds.