As global demand for biorefinery for food, fiber and bioenergy increases, so does the demand for sustainable protein sources. But sustainable biorefinery requires high biomass production on existing farmland, which might be difficult when the goal is to reduce the environmental footprints at the same time.

“Global demands om biomass production for food, fiber and bioenergy will at least be doubled by 2050, and by then we are expected to reduce the greenhouse gas emissions substantially. It is a major task we are facing, and to meet this challenge we are seeking innovative cropping systems to increase biomass production for biorefinery while also reducing the GHG emissions,” says Tenure Track Researcher Ji Chen from the Department of Agroecology at Aarhus University.

Perennial crops fuels microbial metabolic activities

In a new project funded by the Independent Research Fund Denmark Ji Chen plans to study how to manage micro-organisms in the soil to help us produce more biomass and lower the greenhouse gas emissions at the same time.

“The core of the project is to analyze the activity of the enzymes targeting carbon, nitrogen and phosphorus cycling. We want to study how they produce more nitrogen and phosphorus, so it is available for the plants and microorganisms, and also how they help lower GHG emissions,” says Ji Chen.

Other studies provide evidence that the micro-organisms in the soil play a remarkable role in improving plant growth, increasing stress tolerance, as well as protect against pathogens.

“There have been efforts on managing soil microbes for sustainable agriculture before, and the majority of the attempts have failed due to the un-acclimatization and competition with resident microbes. So, despite the large potential, it remains a daunting task to manage microorganisms for higher biomass production and lower GHG emissions. But by looking at the extracellular enzymes in the soil, we might have a better chance,” explains Ji Chen.

“Extracellular enzymes are produced inside the cell by plants and microbes and then secreted outside the cell. Their functions are to break down complex macromolecules into smaller micromolecules that are available for plants and microorganisms. Indeed, the extracellular enzymes are often synthesized to acquire the resources that are limiting plant and microbial growth. For example, our earlier work showed that plants and microbes will stimulate soil phosphatase production when their growth are limited by soil phosphorus availability,” explains Ji Chen.

Extra-cellular enzymes

According to Ji Chen microbially mediated biomass production and GHG emissions are fundamentally associated with soil extra-cellular enzymes, and this may provide new ways of understanding soil microorganisms and maybe even pave the way to manage them better. 

“The CoreEEs project will be the first to investigate eight kinds of extra-cellular enzymes targeting the C-, N-, and P-cycling under differing annual and perennial cropping systems. We will combine the soil extra-cellular enzymes with in situ and lab GHG measurements as well as compare with the long-term biomass yield records from 10 years of experiments at Foulumgaard in Denmark,” says Ji Chen.

The project will provide a unique opportunity to explore the enzymatic functions on biomass yield and GHG emissions as well as the underlaying mechanisms.

“In terms of aiding the green transition of agriculture we will develop novel enzyme indicators to modify cropping systems for higher biomass production and lower GHG emissions,” says Ji Chen.