Algae – Source for By:
Algae – Source for By: Thomas Wencker, Technical Project Management Otto Pulz, Head of Biotechnology Department Robin Knapen, Workgroup Bioplastics Uwe Lehrack, Project Manager Biogenic Materials Lipids 12% Carbohydrates 25% Minerals 9% 10 μm Fig 1.: Nannochloropsis oculata (Photo IGV) IGV GmbH BIOTECHNOLGY Nuthetal, Germany Proteins 54% Fig 2.: typical composition of the green alga Chlorella vulgaris In line with the discussion about climate change and global warming the interest of several companies and governments has been directed towards the general replacement of fossil raw materials by renewables. During recent years different technologies for the general use of renewable resources, such as biomass, plant oil or solar energy, have been developed and implemented all over the world. Today these technologies supply around 20% of the global energy demand and, based on renewable resources, replace the equivalent amount. The application of renewables for biomass conversion into bio-based plastic material is a central field for the future development of an oil-independent society. The social aspect of the global use of biogenic resources, especially in the field of bioenergy, requires an extension of the raw material spectrum which is used for this purpose. Until today photobioreactors (PBRs) for the production of microalgae were mainly developed for use as a nutritional supplement, or for the cosmetics industry and as pharmaceutical ingredients. The biggest closed tubular PBR plant (10,000m² in 2002) is in Klötze, Germany with PBR technology by IGV. Currently, microalgae are the focus of research and development for their application in the production of basic raw materials. The fundamental motivation for this development is the potential utilization of the superior yield per hectare, which distinguishes microalgae from the rest of the classic land crops. The yield per hectare of microalgae is at least twice that of the best land crops (Miscanthus), even when using the simplest technology for the cultivation of microalgae, i.e. the open systems. These open ponds, or raceway ponds, generally consist of basins, in which the microalgae are moved around in direct contact with the atmosphere. Closed systems, which allow better light supply, process control and biotechnological stability due to their closed construction based on pipes, plates or bags, produce a bigger amount of biomass at a high quality level. This technology is state-of-the-art for the production of high value products. But, regarding the market prices of land crops, the price for biomass from the closed systems is still too high (30 to 50 €/kg DM , DM= dry mass) to compete in the raw material markets, because of their more complex technical design. Therefore new thin layer systems are being developed at IGV to fulfill the demand for a biomass source which is able to replace classic fossil resources while avoiding the use of agricultural land needed for food production. The core indications are a biomass production of at least 80 g/m² · d (total plant footprint) with a maximum investment in the plant of 1 million €/ha. 300 300 250 Fig 3.: Yield per hectare Dry matter yield / t/ha · a 200 150 100 50 0 7 6 7 Rape Grain Wood Corn Miscanthus Open Systems Land crops 14 25 60 150 Closed systems Microalgae Thin layer systems 42 bioplastics MAGAZINE [05/11] Vol. 6
Basics Bioplastics? The utilization of microalgae biomass for the production of bioplastics can be performed along different pathways. The typical composition of the green alga Chlorella vulgaris is shown in Fig 2. The composition shows the fraction of carbohydrates which can be processed to a biopolymer via the pathways of starch conversion. In addition, this fraction has a certain content of polysaccharides, such as cellulose, which also appear as raw materials for a compostable bioplastic. The largest fraction, which is typical for most algae strains, the proteins, has not so far been used for bioplastic production above laboratory scale, but promising current R&D results show the technical feasibility. Thirdly, the lipid fraction, which is currently the subject of intense discussion by the biofuel market, can be converted into products which are equal to fossil oil fractions such as ethylene or kerosene. Apart from the material use of the algal biomass, algae cells generally contain a large amount of different valuable substances which can be important co-products of an integrated biorefinery process. Basically, algae strains can differ from one another at a level which entails a certain necessity of choosing the most suitable algae species after exact fixation of the final product. Hence, the chance for the economic production of microalgal bioplastics is connected to an optimum content of suitable organic components, produced at maximum growth rate. Secondly, the downstream process of converting the biomass has to be optimized regarding energy efficiency and simplicity. For the first step IGV is developing a new generation of photobioreactors – the MUTL technology. This technology combines the financial advantages of open ponds with the technical processing advantages of the closed tubular PBRs, while the production rate per area is increased to the levels mentioned above. The new system for algae biomass production enables prices that can compete with fossil resources and therefore represents a chance of establishing a sustainable renewable biomass production. Issue Areal MUTL biomass productivity Annual areal MUTL biomass productivity Investment in MUTL biomass production www.igv-gmbh.com Value 80 g/m² · d 240 t/ha · a Around 1,000,000 €/ha Fig 4.: Photobioreactor (Photo: IGV) Info: Founded in the early 1960s IGV (the Institute for Cereal crop Processing) has dedicated its work to the applied research and development of customized products, sustainable and effective production processes, practically-oriented technical approaches in the fields of food and baking technology, analytical and quality assurance, renewable raw materials and blue biotechnology. The Institute has a staff of 112 persons (July2011) including about 90 scientists. In the 1990s the IGV “Regrowing Resources” department started its ambitious work in the field of using resources which are rich in starch and/or proteins such as different grains, legumes, oil seed and dairy products. In the field of bioplastics IGV concentrates on the interaction of flours obtained from diverse cereals and legumes. For this purpose IGV possesses the most modern equipment for milling, fractionation and extrusion. Further on IGV is able to use the internal interface to the biotechnology department to develop innovative and modern products based on microalgae biomass. Since the 1980s the IGV ‘Biotechnology’ department, headed by Prof. Pulz, has been working on the field of process and application development for the cultivation of microalgae. In several research projects the potential of microalgae for use in food supplements, functional foods, cosmetics and wellness products, as well as pharmaceuticals, has been examined and developed as far as bringing products to the stage of marketable commodities. The photobioreactor development has led to more than 20 international patents which are the foundation for almost 200 closed photobioreactors supplied by IGV worldwide, mainly based on the tubular principle – the largest singular module ever built has an operating volume of 85,000 litres. New developments are targeting a tenfold reduction in production costs, which is a requirement for entry into the big markets of biofuels and CO 2 capture. bioplastics MAGAZINE [05/11] Vol. 6 43
