The activities ofβ-xylosidase, xylan acetylesterase and arbinofuranosidase were measured using 1 mM p-nitrophenylxylopyranoside, p-nitrophenylacetate and p-nitrophenylarabinofuranoside, respectively prepared in sodium citrate buffer (0.1 M, pH 7.0). One mL of reaction mixture containing 0.2 mL of crude enzyme solution, 0.3 mL of sodium citrate buffer (0.1 M, pH 7.0) and 0.5 mL of substrate was incubated at 80 °C for 30 min. The reaction was terminated by adding 2 mL sodium carbonate-bicarbonate buffer (1.0 M, pH 10.0). The activities were determined using p-nitrophenol standard curve (1-10 μg mL-1) drawn using absorbance values measured in spectrophotometer at 400 nm. One unit of the enzyme is defined as the amount of enzyme that liberates 1μmole of p-nitrophenol mL-1min-1 under assay conditions.

Assays for β-Xylosidase, acetylesterase and arbinofuranosidase

ThecircadianrhythmofbimodalO2uptakeofcontrolandeffluenttreatedfisheswerestudiedseparatelyat28°±1°C.TheamountsofO2extractedfromwaterandairwereseparatelydeterminedforadayatregularintervalsof3hreach.TotalO2uptakeateachtimewasobtainedbysummingupthevaluesforaquaticandaerialrespirationobtainedatthecorrespondingtime.Throughoutthepresentstudy,theinitialO2contentofthewaterwaskeptconstant(6±0.5mgF1)

CircadianrhythmofbimodalO2uptake