Polypropylene (PP) is a plastic we come across all the time in a wide range of everyday products – from food containers, drinking straws, and water bottles to washing machines, furniture, and car fenders. It is the second most widely used thermoplastic (after polyethylene) with a global consumption in 2008 of approximately 44 million tons. Though it is currently derived from oil, that could change in the future if the brains at Braskem and Novozymes succeed in developing new technology to convert sugar into polypropylene.
In all physical respects, polypropylene made from sugar is identical to polypropylene made from oil: same chemical composition, same flexibility, same durability. The important difference is that one originates from renewable sugarcane while the other comes from a resource that contributes to global warming and is destined to run out one day. Importantly, the use of sugarcane results in reduced greenhouse gas emissions when used as a substitute for petroleum in polypropylene production. In addition, because the price of oil fluctuates, the price of polypropylene fluctuates with it. More stable and cheaper prices are therefore expected to be other advantages of using sugar instead of oil to make polypropylene.
First-generation green PP
Given its green credentials, there is a large potential market for the new sustainable polypropylene derived from sugar. Braskem of Brazil is one company determined to explore this new market after having certified the first worldwide green polypropylene made with first-generation technology at laboratory scale two years ago. They have ambitious plans to commercialize the product and go into full-scale production with more advanced and competitive technology in future, and that is why they contacted Novozymes.
Their joint research with Novozymes’ scientists in Denmark and the US led to a partnership agreement announced during the COP15 conference in Copenhagen in December 2009. Novozymes will use its technology and know-how to help Braskem develop large-scale production of polypropylene from sugarcane. Braskem is the largest petrochemical company in Latin America and is the first major chemical company to sign a partnership with Novozymes.
“This partnership is an important step toward creating a bio-based economy, in which oil-based products are gradually replaced with bio-based products,” says Thomas Grotkjær, Business Development Manager in the Conversion of Renewables department at Novozymes and a key person in the partnership with Braskem. “Novozymes has traditionally been in the enzyme business but it became obvious to us that we could use our microorganisms and fermentation technology in other applications to expand the whole bio-based economy. Here is a prime example and the aim of the partnership is to put a new polypropylene product onto the world market.”
Ethanol to plastic
In the mid-1970s, Brazil was the first country in the world to blend gasoline for cars with fuel ethanol made on a large scale from homegrown sugarcane. Today, Brazil is the prime producer of ethanol from sugar and has become the largest exporter of fuel ethanol in the world.
Sugarcane grows efficiently in Brazil with little need for fertilizer, and there is a plentiful supply of ethanol made from sugarcane on the Brazilian market. Indeed, one of Braskem’s sister companies within the Odebrecht Group is a sugar and ethanol producer. So ethanol was the natural choice as the starting point for the production of green polypropylene.
The new polypropylene conversion process under development will require a new fermentation process with new microorganisms, and that is where Novozymes’ know-how comes in.
Novozymes has a strong research team in what is known as the “Renewable Chemicals and Metabolic Engineering platform.” The Metabolic Engineering group at Novozymes was set up to support projects for the development of proprietary organisms to enable novel metabolic pathways to ferment sugar into valuable chemicals.
Under the terms of the joint development agreement with Braskem, initial development work will run for at least five years. Upscaling and further commercial development will take place in a pilot facility before a large-scale plant is constructed in Brazil and commercial products enter the market. So it is still early days before a product is manufactured and ready to be sold.
From PE to PP
This is not Braskem’s first venture into green plastics. In April 2009, Braskem began building a 200,000 tons/year green polyethylene (PE) plant in Brazil. Ethanol from sugarcane will be used as the raw material, and the plant will be fully operational by the second half of 2010.
Polyethylene can be made economically from ethanol and that makes it competitive with polyethylene made from oil. Its investment in the plant for green polyethylene encouraged Braskem to investigate the production of another thermoplastic, polypropylene, from ethanol.
“Braskem was the first company in the world to produce a certified 100% renewable polypropylene on an experimental basis. The partnership with Novozymes will further boost Braskem’s technology development and be a key step in the company’s path to consolidate world leadership in green polymers,” says Bernardo Gradin, CEO of Braskem.
His counterpart at Novozymes, Steen Riisgaard, adds: “We live in a world where oil is limited and expensive, and the chemical industry is looking for alternatives to its petroleum-based products. Novozymes’ partnership with Braskem is a move toward a green, bio-based economy in which sugar will be the new oil.
