Optimisation for assay of fluorescein diacetate hydrolytic activity as a sensitive tool to evaluate impacts of pollutants and nutrients on microbial activity in coastal sediments.
Fluorescein diacetate (FDA) assay has been widely applied in coastal research to quantify microbial activity in sediments. However, the present FDA assay procedures embodied in sediment studies potentially include operational errors since the protocol was established for studies of terrestrial soil. In the present study, we optimised the procedure of FDA assay using sandy and cohesive sediments to improve experiential sensitivity and reproducibility. The optimised method describes quantitative measurement of the fluorescein produced when 1.0g of fresh sediment is incubated with 50mM phosphate buffer solution (pH: 7.3) and glass beads (2g) at 35°C for 1h under a rotation of 50rpm. The covariation coefficient of the optimised method ranged from 1.9% to 3.8% and the method sensitivity ranged from 0.25 to 1.57. The improved protocol provides a more reliable measurement of the FDA hydrolysis rate over a wide range of sediments compared to the original method.
Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, 361005, China.
Shan
S
Jiang
Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, 361005, China.
Jing
J
Huang
Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, 361005, China.
Haoliang
H
Lu
Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, 361005, China.
JingChun
J
Liu
Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, 361005, China. Electronic address: ycl@xmu.edu.cn.
Chongling
C
Yan
D002681:China; D004777:Environment; D005452:Fluoresceins / Q000737:chemistry / Q000378:metabolism*; D019015:Geologic Sediments / Q000032:analysis / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008828:Microbiological Techniques / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014874:Water Pollutants, Chemical
D005452:Fluoresceins; D014874:Water Pollutants, Chemical; C018506:diacetylfluorescein
Coastal sediment; Enzyme assay; Fluorescein diacetate; Microbial activity; Optimisation