BioEconomy


	The bio-economy - clean, clever and competitive ...
	Case Studies Taken from: The Application of Biotechnology to Industrial Sustainability – A Primer; OECD; 2002. This is a summary version of the full OECD report.The Application of Biotechnology to Industrial Sustainability, available for purchase from the OECD website – www.oecd.org . Fine Chemicals Given the cost of developing new bio-processes and bioproducts, it is not surprising that some of the first applications of industrial biotechnology appear in the pharmaceutical and fine chemicals segment of the chemical industry, where the value of the products can bear the cost of technology development. It has long been known that enzymes can catalyse certain chemical reactions with high efficiency and specificity. Since 1970, Tanabe Seiyaku (Japan) has used enzymes derived from certain micro-organisms to produce amino acids. Immobilising the enzymes on a surface so they could be used again and again led to 40% cost savings. Improving this system of immobilisation of the micro-organisms to optimize the performance of the enzymes yielded a further 15-fold increase in productivity (i.e., the ratio of product yield to starting material used), resulting in a major reduction of costs and waste. Enzymes usually function in an aqueous solution and this can reduce the requirement in equivalent conventional chemical processes for organic solvents that will later need to be recycled or disposed of by incineration. Biochemie (Germany/Austria), a subsidiary of Novartis, has developed an enzyme-catalysed process for manufacture of the antibiotic cephalosporin. The efficiency of the enzymes was optimised by genetically modifying the micro-organisms that produce the enzymes. When compared to the conventional chemical process, the enzymatic process produces 100 times less waste solvent to be incinerated and, as a result, the cost of production and the potential environmental impact of the process are both reduced. Metabolic engineering is a technique which involves genetically engineering a micro-organism to contain all the enzyme steps for a series of reactions leading to a particular product and then uses the cell metabolism to drive the reaction. In effect, the cell then becomes a highly efficient mini-reactor for synthesising that product. Hoffmann La-Roche (Germany) now uses a metabolically engineered micro-organism to produce vitamin B2. This has enabled the company to reduce a six-step chemical process to one step. As a result, use of non-renewable raw materials has decreased by 75%, emissions of volatile organic compounds to air and water have decreased by 50% and operating costs have decreased by 50%. Similarly, DSM (Netherlands) has used a metabolically engineered micro-organism to reduce the waste produced in the manufacture of cephalexin 3 to7-fold. This has allowed the company to reduce production costs so that it can compete effectively in international markets. Intermediate Chemicals Other case studies indicate that, once the underlying biotechnology has been developed and understood, lateral application can occur in other areas. Thus, biotechnologies developed at high cost in the pharmaceutical and fine chemicals segment of the chemical industry can be adapted and applied at lower cost to produce lower value products, such as intermediate chemicals for synthesis of other chemicals or plastics. S-chloropropionic acid is an intermediate chemical used in the synthesis of certain herbicides. The “S” indicates that the molecule is chiral, that is, one of two asymmetric isomers (the other isomer is the “R” form). The “S” isomer is the one that is biologically active. Conventional chemical procedures for separating chiral molecules are often energy intensive, or require the use of additional chemicals which subsequently require disposal. A biological method for separating chiral molecules involves using a micro-organism that selectively degrades one of the two isomers, leaving the other in essentially pure form once it has been isolated. Avecia (United Kingdom) has developed a bioprocess for producing pure Schloropropionic acid that uses a Pseudomonas bacterium to selectively degrade the “R” form. Mutation, selection and adoption of sophisticated means of fermentation resulted in a four-fold increase in productivity, while use of genetic modification to optimise performance even further resulted in an additional five-fold increase in productivity. The bioprocess results not only in lower production costs but also in less waste by-product that requires treatment and disposal. Mitsubishi Rayon Company (Japan) produces acrylamide, a chemical used to produce acrylic polymers. The conventional chemical process for producing acrylamide from acrylonitrile involves high temperature and the use of either a copper catalyst or sulphuric acid. Mitsubishi Rayon has developed a bioprocess which instead uses a naturally occurring enzyme, nitrile hydratase, to catalyse the conversion of acrylonitrile into acrylamide. The performance and yield of this enzyme has been optimised by genetically engineering the micro-organism which naturally produces the enzyme. The enzyme-catalysed process uses 80% less energy, saves costs and yields higher purity acrylamide than the conventional chemical process. Polymers The conventional chemical process for producing certain polyesters involves the use of either a titanium or tin-based catalyst with solvents and inorganic acid at high temperature (200^oC). Baxenden Chemicals (United Kingdom) has developed a bioprocess that uses the enzyme lipase from the yeast Candida antarctica to catalyse the polymerisation reaction at a much lower temperature (60^oC). The lipase gene was transferred into a genetically engineered industrial strain of E. coli bacterium to reduce the cost of producing the enzyme. The enzyme-catalysed polymerisation process, when compared with the conventional process, eliminates the use of organic solvents and inorganic acids and yields energy savingsof about 2000 megawatts annually at full industrial scale operation. The polymer from the bioprocess also has a more uniform polymer chain length. This results in a melting point over a narrower range of temperature than the conventional polyester, making it more valuable for use as a hot-melt adhesive. Thus, there were both environmental and economic benefits from implementing the enzyme-based bioprocess. Food Processing Often, food processing uses large quantities of water and produces large quantities of organic waste. Biotechnology can help reduce water usage as well as the production of organic waste. For example, Pasfrost (Netherlands) has developed a biological treatment system for water in its vegetable processing facility that has reduced water use by 50% and led to significant cost savings. Similarly, Cereol (Germany) has implemented an enzyme-based system for the degumming of vegetable oil during purification after extraction. This bioprocess was compared with the conventional degumming process that used sulphuric acid, phosphoric acid, caustic soda and large quantities of water. The enzyme system eliminated the need for treatment with strong acid and base, reduced water use by 92% and waste sludge by 88% and resulted in an overall cost reduction of 43%. Cargill Dow LLC (United States) has developed polylactic acid (PLA), a biopolymer that not only involves the use of bioprocesses (developed using biotechnology) that are energy and materials efficient but also utilises a renewable agricultural feedstock, corn. PLA is not only recyclable, but also biodegradable, and can be composted. It can functionally replace plastics such as nylon, PET, polyester and polystyrene and life cycle analysis shows that it can do so with a net fossil fuel saving of 20-50% and at a cost which reflects the lower cost of energy and raw material in its manufacture. In the medium term, advances in biotechnology will allow PLA to be produced also from the cellulose found in agricultural and forest by-products. The plastic will then become a net sink for carbon sequestered from the air by crops and trees. Cargill-Dow has constructed a plant in Nebraska, USA, that will produce 140,000 tons of PLA annually. Food Processing Often, food processing uses large quantities of water and produces large quantities of organic waste. Biotechnology can help reduce water usage as well as the production of organic waste. For example, Pasfrost (Netherlands) has developed a biological treatment system for water in its vegetable processing facility that has reduced water use by 50% and led to significant cost savings. Similarly, Cereol (Germany) has implemented an enzyme-based system for the degumming of vegetable oil during purification after extraction. This bioprocess was compared with the conventional degumming process that used sulphuric acid, phosphoric acid, caustic soda and large quantities of water. The enzyme system eliminated the need for treatment with strong acid and base, reduced water use by 92% and waste sludge by 88% and resulted in an overall cost reduction of 43%. Fibre Processing Large quantities of energy, water and chemicals are used to bleach and treat natural fibres formaking textiles and paper. Enzymes can help reduce some of these input costs and associated environmental impacts. For example, Windel (Netherlands) uses an enzymatic process to reduce the energy and time required to wash hydrogen peroxide bleach from textiles before dyeing. Use of the enzyme made it possible to reduce the temperature and volume of the second wash from 80-95^oC to 30-40^oC, resulting in a 9-14% saving of energy, a 17-18% saving of water and an overall cost saving of 9%. This is very significant in the highly competitive textile industry because margins are generally quite small. Domtar (Canada) has begun to use the enzyme xylanase, supplied by Iogen Corporation(Canada) as an auxiliary brightening agent (this process is called “bio-bleaching”) for wood pulp in paper-making. The enzyme opens up the lignin structure of the wood pulp so that it takes 10-15% less chlorine dioxide to achieve the desired level of brightness. Iogen has reduced the production cost and improved the performance of xylanase by genetically engineering the fungus from which it is extracted. The use of xylanase has helped Domtar reduce the amount of organically bound chlorine in waste water by 60% and the cost of bleaching chemicals by 10-15%. Oji Paper (Japan) has also used xylanase to achieve similar reductions in the requirement for bleaching chemicals and in levels of organically bound chlorine in its waste water. In addition, it produces its own xylanase on-site by fermentation so its input costs are reduced even further. Mining and Metal Refining Billeton (South Africa) has developed a bioprocess (“bio-leaching”) to liberate copper from sulphide ore. The bioprocess uses naturally occurring bacteria to oxidise the sulphur and iron present in the ore at ambient temperature. The conventional process for isolating the copper from the ore involves transporting the mined ore to a smelter where the impurities are driven off at high temperature. The bioleaching process is carried out at the mine site. This saves the cost and energy required to transport the ore and also eliminates the emission of large quantities of sulphur oxides, arsenic and other toxic metals into the atmosphere by the high temperature roasting process. After the copper is extracted from the acidic leach water, the waste water is neutralised and toxic substances such as arsenic are immobilised in a stable form stored at the mine site. The bio-leaching process can be used to process low-grade ores and arsenic containing ores that could not be processed effectively by high temperature smelting. The capital cost requirements of the bio-leaching process are 25% less than for building a smelter. Bio-leaching currently accounts for 20-25% of world copper production. Budel Zinc (Netherlands) is a major producer of zinc. The acidic waste water from its zinc refinery contains zinc and other metals (tin, copper, nickel, manganese, chromium, lead and iron). The conventional process for treating this waste water involves neutralising it with lime or limestone, which results in large quantities of gypsum contaminated with heavy metals. Budel has developed a bioprocess that uses sulphate-reducing bacteria to capture and recycle zinc and other metals in its waste water as metalsulphide precipitate. The metal sulphide precipitate is recycled back into the refinery feedstock. This process has resulted in a 10 to 40-fold decrease in the concentration of heavy metals in the refinery wastewater and eliminated the production of metal-contaminated gypsum which is a hazardous solid waste by-product. Energy Examples of biotechnology applications in the energy sector occur in both the conventional fossil fuel and the renewable energy segments of the industry. Conventional fossil fuels are usually extracted from deposits buried below the surface of the earth. Drilling of oil wells requires the use of substances called drilling fluids or drilling mud. These substances help lubricate the drill and its pipe as well as hold open the well bore. Drilling fluids are designed to deposit a low permeability layer on the surface of the borehole to limit leakage of the drilling fluid into the oil-bearing formation and to prevent invasion of solids into the oil production zones. Once the well is drilled to the desired depth, the low permeability layer must be removed in order to maximize oil production rates. Traditional drilling fluids are muds – dispersions of clay minerals in water and oil where the clay provides the required viscosity and the oil provides the lubrication. These muds pose two problems: (i) the oil used in their formulation can have negative environmental impacts and requires treatment (ii) the strong acid required to remove the low permeability layer is toxic to the environment, corrodes equipment and does not uniformly remove the low permeability layer. M-I and British Petroleum Exploration (United Kingdom) are now using a drilling fluid containing mixtures of bio-organic polymers such as xanthan gum, which provides viscosity, and starch or cellulose, which acts as a binder. The formulation also contains an inert solid called a bridging agent that has a particle size allowing it to bridge pores in the structure of the rock being drilled. This formulation is non-toxic and avoids the problems of conventional drilling muds: (i) there is no oil or other component which requires treatment before release into the environment; and, (ii) the enzymes used in removing the low permeability layer not only perform better but also do not corrode equipment or pose environmental hazard. Biotechnology has been used to optimise the characteristics of these enzymes (cellulase,hemicellulase, amylase and pectinase) to work under the conditions found in a borehole. Although the use of bio-organic drilling fluid systems is in its early days, it appears in a number of cases that their performance is satisfactory and permit cost savings of USD75,000 – 83,000 per well drilled. Ethanol is one renewable fuel whose production is increasing rapidly in response to the need for transportation fuels that produce lower net emissions of greenhouse gases (GHG). Ethanol is produced by fermentation of sugars (such as glucose) using brewers’ yeast. The sugar can come from cornstarch. It takes considerable energy to produce corn, however, so the net reduction in GHG emissions is around 40-50% when ethanol from corn is used to replace gasoline (petrol). If wood cellulose and waste materials are used as the source of sugar to produce ethanol, the net reduction in GHG emissions is larger, around 60-70%. Therefore cellulose-containing materials are, from a GHG perspective, the material of choice for producing ethanol. However, the lignin in woody plant material can prevent full conversion of cellulose into fermentable sugar. Iogen Corporation (Canada) has developed a process utilising cellulase enzymes that maximise the conversion of cellulose into fermentable sugar. The yield and activity of the cellulose enzymes has been optimised using biotechnology. Iogen is in the scale-up phase of the technology and indications are that the cost of ethanol produced in this manner will be competitive with the cost of gasoline produced from oil costing USD25 per barrel. [The main applications] [Top of the page] Taken from: The Application of Biotechnology to Industrial Sustainability – A Primer; OECD; 2002. This is a summary version of the full OECD report.The Application of Biotechnology to Industrial Sustainability, available for purchase from the OECD website – www.oecd.org .