Industrial biopolymers – between children’s shoes and seven-league boots
The International Symposium on Biopolymers (ISBP) was held in Stuttgart between 4th and 7th October 2010. The event organisers also held a special focus day on industrial applications, as suggested by BIOPRO. The conclusions drawn from the ‘Industry Day’ can be summarised as follows: methods are becoming increasingly mature, production capacities are growing and the price of biobased polymers and bulk chemicals is becoming more attractive. However, many developments still need to be taken further and still need to prove their worth.
The company Metabolix can look forward to a promising future, if everything goes to plan. In early May 2010, the company received American Food and Drug Administration (FDA) clearance for the formulated products MirelTM F1005 and F1006, food contact injection moulding grades for use in food contact applications. The two polymers are made from Mirel, a biobased and biodegradable plastic consisting of biotechnologically produced polyhydroxyalkanoate (PHA).
Quality justifies the price
Getting products authorised by the FDA and other regulatory authorities is extremely important for the Cambridge (MA)-based company as it opens the door to a market that has particular requirements of plastics materials, from which Metabolix directly benefits. Tom Ramseier, head of microbiology at Metabolix, informed the audience that the price of one kilogram of Mirel is around US$ 5 (around 3.55 euros). To command such a high price, a plastic must have special properties in order to stimulate market interest. It is highly unlikely that Mirel F1005 and F1006 will be used on vegetable counters as packaging for corn on the cob or tomatoes; standard clingfilm does the job adequately enough. The company expects the two products to be used for special applications, as they remain stable at a broad range of temperatures, i.e. they can be stored in freezers, put into boiling water or used in microwave ovens. It is not yet known what interest the food packaging market has in the products. Metabolix' executives also intend to target Mirel at markets other than food packaging.
Expanding production capacity
Metabolix is now able to produce relatively large quantities of its products. The first large-scale Mirel production (Clinton I) plant began operating in Iowa in 2009. The Clinton I plant has a capacity of around 50,000 t per year, which is relatively low compared to the 260 million t that are produced around the world every year. Nevertheless, Metabolix hopes to gain greater market share with biobased and biodegradable PHAs over the next few years. Ramseier considers around one million t of Mirel per year to be a realistic production capacity.
Biobased polymers are only one of the business areas companies like Metabolix choose to be involved in. Another, equally interesting market is bulk and platform chemicals. Hydrocarbons with backbones consisting of two to five carbon atoms are important prestages in the industrial polymer chemistry sector. It is assumed that some time in the future biobased raw materials will become an important additional fuel besides petrol, or maybe even the only alternative. Ramseier believes that the so-called C4 compounds composed of four carbon atoms can reach a market volume of 2.5 billion US$ per year and that special applications involving C4 compounds will reach a market volume of around 800 million US$.
Decomposition, separation, conversion
Prof. Dr. Thomas Hirth, director of the Fraunhofer Institute of Interfacial Engineering and Biotechnology in Stuttgart provided further details on the issues introduced by Ramseier. Hirth spoke about the potential of renewable resources as the basis for platform chemicals. He expressed his belief that integrated approaches, in which biology, biomechanical engineering, chemical engineering and polymer chemistry specialists need to work even closer together than they have done before, are necessary to use this potential to the full.
In order to turn the vision into reality, Hirth referred to the need for biorefinery facilities to decompose biomass, separate it into basic molecules and then subsequently convert it into industrially usable hydrocarbon compounds. According to Hirth, plant biomass consists of 39% cellulose, 30% lignin, around 26% other carbohydrates and 5% other plant materials. The biomass components in plants are not neatly separated from each other. The biomass components of plants form huge branched, stable and fairly heterogenic molecules in the form of lignocellulose and hemicellulose. These hydrocarbons will be decomposed in refineries, thus preparing them for technical downstream processes. Hirth referred to three possible ways of converting biomass: biotechnologically, chemically and thermochemically. Biotechnological procedures require the lowest temperatures, and least energy, to process biomass, whilst thermochemical procedures require the highest. For this reason, biotechnological processing is seen as the method of choice. However, biotechnological processing will only be possible with microorganisms and enzymes that are effectively able to process the individual biomass components. The search for effective biological tools to process biomass is a huge area of research. At present, thermochemical methods are the only way to decompose some types of biomass. For example, lignocellulose is decomposed into cellulose, hemicullulose and lignin by boiling the material in an ethanol-water mixture (60:40) at 250 °C.
How different products are generated
The individual complex compounds contained in biomass differ in their molecular composition, which explains why their decomposition also leads to different products. Cellulose consists of glucose that can be converted into ethanol, and ethanol can be used to produce ethylene or polyethylene. In addition, lactic acid and polylactic acid are also based on glucose. The platform chemicals succinic acid and 5-hydroxymethylfurfural can be produced from glucose. Hemicellulose principally generates sugar; phenolic compounds that can be used for polymer production can be isolated from lignin.
Through the use of biorefineries, biomass becomes a broad base for the production of polymers and platform chemicals. Hirth believes that the biggest challenges related to the successful implementation of the biorefinery concept are: the need to further develop existing processes and make them suitable for large-scale processes. In addition, they need to be designed in a way that enables them to be integrated into existing production methods used by the chemical industry.
Biorefinery – standard model of the future
Thomas Schäfer from Novozymes, which is based in Bagsvaerd/Denmark, believes that the biorefinery concept opens up huge opportunities for his company as well as others. Novozymes is the largest enzyme producer in the world. Biorefinery concepts lead to an increase in the demand for technical enzymes that catalyse the decomposition and conversion of biomass. Although process engineers, biotechnologists, polymer chemists and process developers still have a lot of work ahead of them, Schäfer is nevertheless convinced that biorefinery concepts have huge potential. "Biorefining will become the standard in our endeavours to replace petrol," Schäfer predicts.
He sees the efforts to achieve greater sustainability as being a major driver of industrial biotechnology. He thinks that the biotechnology industry needs to produce so-called "bioidenticals", molecules that are derived from biomass but that have a structure identical to the standard molecules used in the chemical industry. Schäfer believes that biotechnology needs to respond to the key question as to whether the price of biotechnological products can compete with that of traditional products. Any such response needs to take into account classical bioprocess-related parameters such as product yield and productivity. In addition, biotechnology will also have to focus on solving issues such as the provision of substrates, by-products and substance conversion.
In Schäfer's opinion, there is a major need for processes that produce plastics and platform chemicals without using petrol; one example he gives is the production of polypropylene. He envisages a shortage of polypropylene from 2015 onwards due to the fact that demand will exceed availability, which currently stands at around 45 million t per year. He also believes that the synthesis of polypropylene from biobased ethanol will be able to relieve this bottleneck.
Novozymes sees great opportunities in developments of this kind, given that the company is planning far more than the production of platform chemicals and polymers. The company believes that the production of platform chemicals and polymers will also contribute to making enzymes and related process chains more important. The company's business model targets this very point in the biotechnological and bioindustrial value creation chain, namely the development of technical enzymes and processes and their implementation in collaboration with industrial partners such as Braskem, ADM, Cargill and others.
Novozymes and its partners have recently developed a process that enables bioethanol to be produced from plant material. Novozymes expects a gallon of bioethanol to cost two dollars, or around 0.5 euros a litre. The Brazilian company Braskem has announced its intention to turn this concept into reality.
China – global market leader
The industrial importance of biomass, and hence the interest in bioplastics, is also increasing in China. In his presentation, G. Chen from Tsinghua University in Beijing reported that China already uses fermentative methods to produce several thousand t of biobased plastics or basic materials used for plastics production, including 20,000 t PHA, 5,000 t polylactide (PLA) and 10,000 t polybutylene succinate (PBS). Pilot plants have been built to produce polymers such as polyethylene or polytrimethylene terephthalate (PTT).
The Chinese government supports the development of biodegradable plastics by limiting the use of non-degradable plastics, for example plastic shopping bags, whose use has been restricted since 2008. A projection of the potential number of consumers worldwide shows that there is a gigantic market for biodegradable plastics that can also be produced from biomass. China is already the largest producer of biobased plastics. With the exception of PLA, China is the worldwide leader in the production of all relevant plastics from renewable resources.
The Industry Day was a success
The Industry Day, which was held for the first time following the initiative of BIOPRO Baden-Württemberg, provided a wealth of information for ISBP. The symposium, which in previous years mainly dealt with basic aspects, now also focused on markets and industrial applications. The Industry Day showed that the biopolymer research in industrial countries is making great progress. Although some approaches, for example biorefinery concepts, are still at the early stages of development, they are nevertheless very promising. The methods for using renewable resources are improving and the price of biobased products is gradually reaching a level at which it can compete with petrol-based products.
Bioplastics production capacities are still quite small. With regard to the huge quantities processed by the plastics industry every year, the yearly production of individual bioplastics producers is relatively moderate. However, if companies like Metabolix are aiming to achieve capacities of around 1 million t per year, this gives a clear signal: the biopolymer industry is putting on its seven-league boots.