Convert lactose to galactooligosaccharide and optimize intestinal health.

Food fermentation processes rely on both endogenous and microbial enzymes to degrade starches, lipids, proteins, anti-nutritional and toxic substances. In some cases, microbial enzymes associated with indigenous fermentation processes exhibit unusual properties. Microorganisms are the primary source of many industrial enzymes. About 50% of them originate from fungi and yeast, 35% from bacteria, and 15% are either of plant or animal origin.

Microbial lactase can hydrolyze lactose in milk into glucose and galactose. It is used to address the problem of lactose intolerance, which is prevalent in a number of developing countries. Researchers at Agriculture and Agri-Food Canada have developed and want to commercialize a technique that produces several natural thermostable and cold-temperature active lactases from GRAS microorganisms grown in cheese whey.

Investigators grew GRAS microorganisms in waste cheese whey. The enzymes were released by homogenization and were partially purified. The lactases actively hydrolyzed lactose and synthesized oligosaccharides at different temperatures. Some of these enzymes were overproduced by cloning lactases genes in Escherichia coli using different plasmid vectors. They were purified using salt fractionation and chromatography techniques.

Lactase of Streptococcus thermophilus was overproduced more than 1000-fold in E. coli by harnessing recombinant DNA technology. Using some of these lactases, up to 50% of concentrated lactose in whey permeate was converted into galactooligosaccharides as bifidogenic factors and nutraceutical products. Dietary oligosaccharides, which can be fermented by intestinal bacteria, are beneficial for intestinal health.

The scientists want to collaborate with an industrial partner to conduct pilot tests and bring the research to the pre-industrial stage. The industrial partner will need some specific equipment for the production of native and recombinant lactases: a fermentor, homogenizer or sonicator, and a centrifuge. The study of recombinant lactases also requires chromatography equipment.

Galactooligosaccharides are a mixture of oligosaccharides consisting of D-glucose and D-galactose. They are produced from D-lactose via the action of the enzyme beta-galactosidase obtained from Aspergillus oryzae. Galactooligosaccharides are not usually digested in the small intestine. They are fermented by colonic bacteria. This could lead to changes in the colonic ecosystem in favor of some bacteria, such as bifidobacteria, which may have health benefits, including protection against certain cancers and lowering of cholesterol levels.

Further information. Steve Bittner, Commercialization and Business Development, Agriculture and Agri-Food Canada Food Research and Development Centre, 3600 Casavant Blvd. W., St. Hyacinthe, Quebec J2S 8E3, Canada; phone: [phone]; fax: [phone]; URL: http://res2.agr.gc.ca.