ENZYMES FROM MARINE PHYCOPHAGES THAT DEGRADE CELL-WALLS OF SEAWEEDS

Agarase, cellulase and alginate lyase activities from crude extracts o f Aplysia dactylomela Rang, Haliotis coccinea canariensis Nordsieck, L ittorina striata King et Broderip and Diadema antillarum Phillipi were measured in vitro to compare digestive efficiencies against several c omponents of complex seaweed cell walls. Commercial abalone acetone po wder (AAP, an extract from Haliotis sp.; Sigma, Ref. A-7514) and purif ied (Sigma, Ref. A-6306) and non-purified agarases from Pseudomonas at lantica were used with the same objective. Optimum conditions for agar ase and cellulase activities were 40-degrees-C and pH 6.0. For alginat e lyase, optimum temperature and pH were species-dependent. Highest re ducing sugar release was shown by crude extracts from A. dactylomela. These crude extracts displayed high agarase activity compared with bac terial agarases at 40-degrees-C, and were significantly higher at 25-d egrees-C. AAP and crude extracts from L. striata and D. antillarum exh ibited high specific activities on all the substrates. Cold extract fr om Gracilaria spp. was the best substrate with which to measure agaras e activity.