TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compound: The lactone is a homoserine lactone e.g. an N-acyl-L-homoserine lactone such as N-(3-oxododecanoyl)-L-homoserine lactone or N-butyryl-L-homoserine lactone.    TECHNOLOGY FOCUS - BIOLOGY - Preferred Microorganism: The microorganism includes an aerobic or anaerobic bacterium, fungus, algae or protozoan. The aerobic bacterium is an Aeromonas, Burkholderie, Escherichia coli, Flavobacterium, Microbacterium, Pseudomonas, Salmonella or Staphylococcus strain. The anaerobic bacteria is a Desulfovibrio strain. The fungus is yeast, preferably a Candida strain, or a filamentous fungus.Preferred Sources: The acylase is obtained from a plant, animal, or microbe, preferably from bacterial or fungal strain. The bacterial acylase is obtained from an Acetobacter, Acinetobacter, Agrobacterium, Alcaligenes, Arthrobacter, Azotobacter, Bacillus, Comamonas, Clostridium, Gluconobacter, Halobacterium, Mycobacterium, Rhizobium, Salmonella, Serratia, Streptomyces, E. coli, Pseudomonas, Wolinella or methylotrophic bacterium strain. The fungal acylase is obtained from a yeast or filamentous fungus. The yeast acylase is obtained from a Candida, Kluyveromyces, Pichia, Saccharomyces, Schizosaccharomyces or Yarrowia strain. The filamentous fungal acylase is obtained from an Acremonium, Aspergillus, Aureobasidium, Chrysosporium, Cryptococcus, Filibasidium, Fusarium, Humicola, Magnaporthe, Monilia, Mucor, Myceliophthora, Neocallimastix, Neurospora, Paecilomyces, Penicillium, Phanerochaete, Piromyces, Schizophyllum, Sclerotium, Sporotrichum, Talaromyces, Thermoascus, Thielavia, Tolypocladium or Trichoderma strain.    TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Conditions: The acylase has a concentration of 0.001-1, preferably 0.01-0.1 g/kg water. It has a pH of 3-10, preferably 5-8; and an optimum temperature of 5-100, preferably 25-50 degreesC. The surface is contacted with the acylase(s) for at least 1-7, preferably 1-2 days.Preferred Components: The composition includes dispersants, surfactants, detergents, antimicrobials, biocides and/or other enzymes including aminopeptidase, amylase, carbohydrase, carboxypeptidase, catalase, cellulase, chitinase, cutinase, cyclodextrin glycosyltransferase, deoxyribonuclease, esterase, alpha- or beta-galactosidase, glucoamylase, alpha- or beta-glucosidase, haloperoxidase, invertase, laccase, lipase, mannosidase, oxidase, pectinolytic enzyme, peptidoglutaminase, peroxidase, phytase, polyphenoloxidase, proteolytic enzyme, ribonuclease, transglutaminase or xylanase. EXAMPLE - Native acylase (150 microg) was added to a water sample (1 ml) from fish tank, which was aliquoted into 1.5-ml methacrylate cuvette. The cuvette was capped and incubated without shaking/stirring for up to 18 days at 23 degreesC. A 60% reduction in the microbial growth was observed from 11th to 18th day incubation as compared with solutions having either 0 or 150 microg inactive acylase.