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Animal feed
Modern biotechnology plays a significant role in the production of micro-ingredients for the feed industry, but in terms of volume and sales, chemically synthesized products have the major share of the total market. However, animal feed is a rapidly growing market for enzymes, with enzyme sales valued at around $120 million world-wide.
Since the common protein sources used in animal feeds (e.g. soya, fishmeal, wheat and maize) are deficient in methionine, lysine, threonine and tryptophan, these essential amino acids are added as supplements to monogastric diets, e.g. for poultry and pigs. Whereas methionine is produced by chemical synthesis (300,000 tons in 1996), lysine, threonine and tryptophan are produced by industrial
fermentation using mutants of Corynebacterium glutamicum and recombinant strains of E. coli.
| Reducing waste |
L-Carnitine, an essential cofactor in the transport of long-chain fatty acids, is a significant new product for intensive animal production. A new biotechnological process developed by Lonza provides a rare comparison of waste generation by chemical and biotechnological processes producing the same product. Compared to the chemical process, the biotechnological process is much cleaner. It
produces about 50% less total organic carbon waste and less than 25% of the wastewater.
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Feed enzymes are designed to degrade components of raw materials that limit digestibility and/or lead to higher levels of excretion of manure, nitrogen and phosphorus. Endoxylanases and phytases are the best-known feed enzyme products. Endoxylanase enzymes hydrolyze certain compounds present in wheat and maize, thereby increasing digestibility of all nutrients and reducing output of manure,
nitrogen and phosphorus. Phytases hydrolyze phytic acid and release inorganic phosphate, thereby avoiding the need to add inorganic phosphates to the diet and reducing phosphorus excretion. If phytase is added to feeds for pigs to liberate phosphate in the feed, phosphate release in manure is reduced by 30%. In a country like the Netherlands, this would reduce the phosphate released into the
environment by 20,000 tons a year. The marginal price increase in the feed cost to farmers (about 0.2%) would be compensated for by a reduced levy on the discharge of phosphate.
| Improving digestibility |
Marshall Agriculture in Scotland use a multi-enzyme product to help poultry digest plant material in their food. Bruce Bielby, the general manager responsible for feed, says that the enzymes improve digestibility, thereby leading to better feed efficiency. "They also make it possible to use cheaper raw materials", he says. In addition, the volume of litter is reduced, there is less
nitrogen pollution, and the litter is rier so that it is easier to keep the birds clean. Pig breeders face the problem that pigs are weaned before their digestive systems are fully mature. Even mature pigs cannot digest plant fibers, with the result that up to 20% of the feed energy is wasted. In 1993, Patrick Dean Limited, a farming company, started to use a multi-enzyme supplement which
enables pigs to break down barley, a cheaper cereal, without any digestive upsets. "Enzyme additives are not medicines", says Peter Fullarton of Forum Products, the company supplying the supplement. "We can't make health claims for them. But there is certainly plenty of evidence of improved digestion." |
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Industrial Sustainability
