Researchers make synthetic starch from carbon dioxide

Rice, potatoes, corn, corn. All of them seem relatively harmless foods that we often don’t need to think twice about. Yet they all constitute a fundamental carbohydrate which is not only a crucial part of the human diet, but is also a main raw material for the bio-industry and a central ingredient in the manufacture of products such as paper and pharmaceuticals. . Starch. It may not seem like changing the way we source our food is a priority in our agricultural industries, but the growing demand for starch-producing crops has led to problems with land and water scarcity, as well as the leaching of pesticides. harmful to the environment. Although it is a seemingly basic food substance, it is one that is of sufficient food and industrial importance to merit consideration for the purpose of making our industries more sustainable.

A team of researchers from the Strategic and Integrative Research Department of the Tianjin Industrial Biotechnology Institute (an institute under the Chinese Academy of Sciences) developed a new way to make starch that eliminates crops from the equation – using only carbon dioxide. in the cultivation process. Although the method is still in its infancy, if developed to become commercially viable, it could be a turning point in making starch more environmentally friendly, without compromising our global food supply.

It’s time to starch

At present, starch is mainly produced by crops such as corn, which fix CO2 through photosynthesis in a process that is said to have a theoretical energy conversion efficiency of about 2%. Now the Chinese the research team developed a new “hybrid system” for making artificial starch using a bioreactor which eliminates the need for plants and has a much faster processing time. In this new method, an inorganic catalyst reduces CO2 to methanol before breaking it down further into carbon sugar units, and finally into polymer starch.

“This artificial starch anabolic pathway relies on recombinant enzymes engineered from many different source organisms and can be tuned to produce amylose or amylopectin at excellent rates and efficiencies compared to other systems. synthetic carbon fixation – and, depending on the metric used, even for field crops, ”the team writes.

The process was created using a computer pathway design, and the team claims it is 8.5 times faster than synthesizing natural starch in corn, converting carbon dioxide into starch. at a rate of 22 nanomoles per minute. The researchers also hypothesized that solar and hydrogen sources could be used to power the process, the man-made process converting the sun to starch at a rate 3.5 times faster than in plants.

“We only need a few hours in the lab to complete the process which takes a few months through the plants,” senior author and research associate Cai Tao told public broadcaster CCTV. “The annual production of starch in a 1 cubic meter (35 cubic feet) bioreactor is theoretically equivalent to the annual yield of growing a third of a hectare (35,500 square feet) of corn regardless of energy input. . “

Producing starch in a laboratory or factory rather than on farms would not only save on land use, but also reduce carbon emissions and provide a greater sense of food security, to both for human consumption and for animal raw materials.

While this may seem like an obvious alternative to traditional starch synthesis processes, there is a catch. The method as it currently exists is far from being economically viable and requires much higher energy rates than what is ecologically sustainable, the first step of converting CO2 to methane alone requiring sufficiently high temperatures and pressures. to potentially require fossil fuels to produce – ultimately proving to be an energy-intensive and expensive process.

Such questions are certainly food for thought, although the project so far provides an important foundation on which to build – not only for starch but in the potential rise of synthetic biology in agriculture more generally.

Synthetic biology in agriculture

A Planned 2020 research article Global food production must be increased by 70% to meet demand by 2050, which current farming methods cannot achieve. As think tank Rethinkx writes, “We are on the cusp of the deepest, fastest and most significant disruption in food and agricultural production since the first domestication of plants and animals ten years ago. a thousand years. “

The agricultural biotechnology market is fixed see growth by 10.7% over the forecast period 2021-2030. This of course extends beyond crops to encompass lab-grown meat and other proteins to feed the burgeoning alternative meat industry – Rethinkx predicting the number of cows in the United States will have declined by 50 % by 2030 as demand for livestock drops.

Growing plants in the laboratory has long been identified as a way to reduce emissions and avoid competition for land use while meeting an increasing demand for food, and researchers at the Tianjin Institute are not alone in their mission to find ways to create the foodstuff of our future that limits our dependence on cultures. Finnish food tech startup Solar food has developed a fascinating method of producing food using electricity, air and a single microbe, a process the group says is 20 times more efficient than photosynthesis. The substance produced is like a type of flour, which the group hopes they can use not only to replace fillers in a multitude of food products, but also to provide a protein base for laboratory-grown fish and – with some modifications – the Palm oil.

With concerns over our use of land and water, it will become increasingly common for innovators around the world to look to other processes that offer a faster, less resource-intensive solution – and which provide an evergreen food source. But we’re not quite there yet, and the Tianjin Institute project certainly requires more research before being economically competitive with existing processes. Yet once these issues are resolved, those solutions will be the ones that will crack the code to strengthen our food systems to meet environmental and human demands.

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