Materials From meat
Materials From meat waste to bioplastics Fig. 1: The ANIMPOL process: From slaughterhouse waste to PHA By Martin Koller Institute of Biotechnology and Biochemical Engineering Graz University of Technology Graz, Austria The 36 month ANIMPOL project (‘Biotechnological conversion of carbon-containing wastes for ecoefficient production of high added value products’) funded by the EU was launched in 2010. ANIMPOL is developing a sound industrial process for the conversion of lipid-rich animal waste from the meat processing industry as a contribution to the production of biodiesel. The saturated biodiesel fractions which negatively affect biodiesel’s properties as fuel are separated and finally used as feedstock for the biotechnological production of polyhydroxyalkanoates (PHA), a versatile group of biopolymers for production of bioplastics. The remaining unsaturated biodiesel represents an excellent 2 nd generation biofuel. The significance of the project is obvious considering the high amounts of available ANIMPOL-relevant waste in Europe (500,000 tonnes of animal waste and about 50,000 tonnes of saturated biodiesel fraction). The principle idea of the project is visualized in Fig. 1. Background PHAs are a well-known family of polyesters accumulated by micro-organisms in nature as an energy reserve. The right photograph in Fig. 1 shows bacterial cells containing PHA inclusions. The diverse desired properties of PHAs are accessible from renewable resources by the biosynthetic action of selected prokaryotes and this opens the door for replacing petrolbased thermoplastics, elastomers, or latexes (see Fig. 2) with these bio-inspired alternatives. Alternative Raw Materials The need for alternative materials, because of the finite sources of fossil reserves, is obvious and generally undisputed. In order to become a competitive alternative on the market, the price of a biopolymer for a certain application must be in the same range as the competing ‘traditional’ plastic. Hence, the costs of PHAs have to be reduced considerably despite the current unstable price of crude mineral oil. Project Philosophy and Schematic The utilization of various renewable feed stocks for production of biochemicals, bioplastics or biofuels, and so coming into competition with food production, is frequently discussed. As an alternative solution, diverse waste streams exist which currently constitute severe disposal problems for the industrial branches concerned, and at the same time do not interfere with the nutrition chain. The utilization of these waste streams is a viable strategy to overcome a potential ethical conflict; it can be considered as the most promising approach in making PHAs economically more competitive. The ANIMPOL project aims at the value-added conversion of waste from 26 bioplastics MAGAZINE [05/12] Vol. 7
Materials slaughterhouses, the animal waste rendering industry, and biodiesel production. Lipids from slaughterhouse waste are converted to fatty acid methylesters (FAMEs, biodiesel). FAMEs consisting of saturated fatty acids, generally constitute a fuel that has an elevated cold filter plugging point (CFPP) which can be disadvantageous in blends that exceed 20% by vol. FAMEs. In ANIMPOL, these saturated fractions are biotechnologically converted towards PHA biopolymers. As a by-product of the transesterification of lipids to FAMEs, crude glycerol phase (CGP) accrues in high quantities. CGP is also available as a carbon source for the production of catalytically active biomass and the production of low molecular mass PHA. This brings together waste producers from the animal processing industry with meat and bone meal (MBM) producers (rendering industry), the bio-fuel industry and polymer processing companies. This synergism results in value creation for all players. The basic scheme is illustrated in Fig. 3, whereas Fig. 4 provides a rough estimation for the available amounts of raw materials in Europe and the amounts of PHA biopolyesters that are theoretically accessible therefrom. Major Objectives of ANIMPOL The project activities are based on a total of 13 main pillars: 1. Design of an integrated industrial process for microbial mediated, cost-efficient production of biodegradable PHA biopolyesters, by starting from waste from slaughterhouses, rendering industry, and biodiesel production. These wastes are upgraded to renewable raw materials. After the end of the project, data should be available for designing a pilot scale production plant. 2. Improvement of the quality of biodiesel by removal of its saturated fraction. 3. Assessment of the raw materials (lipids from animal waste, saturated biodiesel fraction, surplus glycerol from biodiesel production) for the fermentation process by selected microbial strains accumulating structurally diversified PHAs. 4. For improvement of microbial growth and quality, and the amount of the PHA produced, appropriate strains are studied, including recombinant gene expression or host cell genome modification. Microbial growth and the PHA production phase are established to be scaled-up for optimized production of structurally predefined PHAs. Protocols for controlled PHA production are developed aiming at reproducible product quality. 6. Development of an environmentally safe, inexpensive and efficient downstream process for recovery and purification of PHAs. Figure 2: Highly elastic medium-chain length PHA latex produced by a Pseudomonas strain on animal-derived biodiesel. (Picture: M. Koller, TU Graz) Rendering Industry MBM (Meat and Bone Meal) Carbon and Nitrogen source for microbial growth Grude Glycerol 265.000 metric tons/year Catalytically ActiveBiomass (0.4-0.5g/g) ANIMAL Lipids Biotechnological Production of PHAs Polymer Industry PHA 120.000 t (0.3g/g) Animal Waste Lipids 500.000 t/y Saturated Fraction 50.000 t/year PHA 35.000 t (0.7g/g) Slaughterhouses Biodiesel Industry (Transesterification) CPG (Crude Glycerol Phase) Carbon source for - Microbial growth - Low molecular mass PHA accumulation Saturated fraction Carbon source for PHA production Biodiesel Figure 4: Available raw materials for the ANIMPOL process and potentially accessible quantities of PHA biopolyesters Biodiesel (Fatty Acid Alkyl Esters) Figure 3: Application of different waste streams from diverse industrial branches to be utilized for biopolymer production in the ANIMPOL project Unsaturated: Biodiesel High Quality Unsaturated Fraction Excellent 2 nd generation Biofuel! bioplastics MAGAZINE [05/12] Vol. 7 27
