Tapping marine enzymes for use in products.

The scientific community continues to pursue the development of higher-value biochemicals and pharmaceuticals from such fishery wastes as enzymes. With the onset of recombinant-DNA technology, there is also growing interest in cloning genes for novel biochemicals from aquatic organisms for mass production using different expression systems.

According to researchers at the University of California (Institute of Marine Resources, Department of Food Science and Technology, Davis, CA 95616), using enzymes as processing aids has several advantages over the use of chemicals as such aids. They are highly specific, efficiently catalyze reactions and are environmentally friendly.

The enzymes currently in use are mostly hydrolases. Sales of proteolytic enzymes have long dominated the market. However, it's expected that lipases will find greater use industrially in the near future.

Finding the right enzyme for a specific use necessitates an understanding of specific process variables-pH, time and temperature-and material variables-the presence of inhibitors and the chemistry of components. With several thousand new food products introduced annually, there appear to be numerous opportunities for developing unique enzymes.

Enzymes from fish processing wastes have become commercially available for food applications. They should evolve into a significant part of the industrial enzyme market as scientists learn more about special properties that fit the needs of specific applications.

Less than 5% of marine microorganisms have been cultured or identified. Recently, biotechnology companies have focused on developing microorganisms living in these extreme environments as sources of extremozymes. A marine bacillus was the source of a new enzyme that degrades the glucan that causes dental caries from Streptococcus mutans. A thermalvent bacteria, Pyrococcus furiosus, was the source of a beta-glucosidase with an optimum temperature of 100 C and unusual substrate specificity for glycosylation. The enzyme has a half-life of 85 hr at 100 C, which can be improved by using immobilization techniques. This material might be used in modifying food hydrocolloids.

Several marine-based enzymes have found application in the seafood industry. Pepsin sourced from cod and collagenase from crab hepatopancreas are used to remove fish skin and membranes from roe sacs and other products. Trypsin is the limiting enzyme in the fermentation of matjes herring, and the cold-adapted enzyme from cod is commercially available as a fermentation aid. A variety of proteinases and peptidases in squid hepatopancreas reduce the fermentation time of fish sauce from about two years to four months. Lysozyme from Arctic scallop and other fish attack gram-positive bacteria. The scallop enzyme has higher molecular activity than chicken lysozyme, particularly at refrigeration temperatures. The enzyme has been recovered from scallop processing wastes and has potential for application as a preservative in refrigerated foods.

Further information. Norman Haard; phone: [phone]; fax: [phone].