Sustainable plastics from natural sources

“White biotechnology,” also known as industrial biotechnology, describes the production of organic chemicals and/or active ingredients using optimized micro-organisms (yeast or bacteria) and/or enzymes. It offers a myriad of benefits by enabling scientists to develop sustainable and efficient solutions throughout various industries, such as the production of eco-friendly biofuels, bioplastics and biobased chemicals, all of which reduce our dependence on fossil fuels and minimize their environmental impact.

Additionally, white biotechnology facilitates the creation of more efficient and cost-effective manufacturing processes, leading to reduced energy consumption, waste generation and overall resource usage. Through its innovative applications, this field holds the potential to drive a transition towards a greener and more sustainable economy, addressing global challenges while promoting technological advancement.

White biotechnology also contributes to the development of safer and healthier consumer products. It plays a pivotal role in producing enzymes for detergents, textiles and food processing, enhancing the efficiency of these processes while minimizing the need for harsh chemicals.

GEA has always been interested in innovative new methods, especially if they help to conserve resources and enable the ecologically friendly production of alternatives to conventional petroleum-based chemical products. And, believing in this new technology from the start, it was a topic of animated conversations at congresses, in the preparation of cross-departmental expertise and, of course, in the company’s in-house technology center where novel theories were tested and implemented.

A key focus was biobased chemicals and biorefining — processes that use micro-organisms to convert natural, renewable raw materials — such as starch, sugar, cellulose and waste biomass — into a variety of intermediate and end products. Of particular interest were biopolymers. For clarity, whereas regular polymers comprise any class of natural or synthetic substances composed of very large macromolecules, their “bio” cousins are either chemically synthesized from a biological material or entirely biosynthesized by living organisms. These environmentally friendly substitutes for petroleum-based polymers can be used to make, among other things, sustainable plastics. 

Plastic yes. Oil no!

Biopolymers are always obtained from renewable raw materials. But, the term is ambiguous. On one hand, they are used to produce novel substances that are completely biodegradable. This is highly desirable in the case of packaging for takeout food or bags for shipping from online retailers. On the other hand, products such as car fittings need to be robust, reliable and resilient for the longest possible time. Biopolymers also make this possible: they can be used to make plastics that are both durable and meet the same safety standards as those made from petroleum-based polymers. Another advantage of biopolymers is that existing production processes can be easily adapted to produce them. The food and feed sector has long been concerned with the production and utilization of amino acids. Lysine, for example, is used as a feed for livestock. It reduces the consumption of soy, fish meal and wheat and leads to balanced animal nutrition. Enzymatic conversion processes can link amino acids such as lysine to form biopolymers, which can then be used to produce nylon instead of feed. 

Natural power plants: Bacteria

The process in which biopolymers are produced is also natural. “Micro-organisms do that for us,” explains Product Sales Manager, Jens Bühring, an expert in the field of centrifugal separation technology. “In a so-called fermenter, the micro-organisms are first fed with sugar or starch and then produce the desired intermediate products or, sometimes, even finished polymers.”

Fellow separation expert, Burkhard Schiemann, adds: “To motivate our bacteria to produce biopolymers, we first provide ideal environmental conditions. In other words, we feed them up with oxygen, sugar and minerals. The bacteria then feel comfortable and multiply. When there are enough organisms in the fermenter, we change these very positive conditions by removing the sugar from the growth medium or changing the pH of their environment.”

This causes the bacteria to become stressed: they realize that something has changed and that “bad times” are now probably upon them. As a coping mechanism, the organisms store certain substances. These could, for example, be polymers. “For the bacteria, it’s an emergency supply to prepare for whatever’s coming next; for us it’s a valuable and versatile chemical compound that’s highly interesting,” adds Burkhard. 

Full centrifugal power for more sustainability

To turn naturally produced polymers into a competitive product, companies often turn to GEA’s separation technology. “To be able to use these natural factories economically, centrifugation offers a number of advantages,” reports Jens Bühring. “As a mechanical process that can be used to separate the biomass — the total quantity or weight of organisms in a given area or volume — centrifuges are resource-friendly and operate in a very efficient way. Whether that’s working with the raw material or processing the intermediate product, GEA has a lot of expertise in this field and also supplies downstream processing equipment … all the way to the end product.”

The benefits are manifold: “Our customers are already very familiar with many of the upstream process steps, such as material handling and fermentation, and have both the required expertise and equipment. With just a few more steps, that same customer now has access to an additional market,” says Burkhard Schiemann.

Citing lactic acid as an example. In addition to its traditional use as an acidifying agent in the food and beverage industry, it is now widely used as an ingredient for a bio-based and biodegradable plastic called polylactic acid (PLA) thanks to GEA’s active support.

“We can also help our customers with process development,” says Jens Bühring: “This has many benefits because processes that work perfectly well at laboratory scale don’t always transfer to industrial standards (or capacities). To avoid unpleasant surprises, we are happy to assist with our expertise and the appropriate GEA equipment … because nothing is more economical and efficient than planning processes together.”