Determination of absorbance methods in Nannochloropsis oculata
2002
Karakisawa, H. (Niigata-ken. Government Office (Japan))
Abstract Knowledge of Nannochloropsis oculata volume is necessary for the aquaculture of marine fish. A Thoma-Zeiss counting chamber and dry weight measuring are used to determine cell number at the Niigata Prefectural Fisheries and Marine Research Institute, but these methods are erratic and time consuming. Therefore an easier method of measuring Nannochloropsis cell number using a spectrophotometer was investigated. The absorption spectrum bf Nannochloropsis showed four peaks (266, 441, 490, and 683nm) and two valleys (355 and 650nm) . A correlation between dry weight and a 10 absorbance (four peaks, two valleys, and four gaps between peak and valley; e.g. 266-355nm, 441 -355nm, 490 - 650nm, and 683 - 650nm) was found. 266nm showed the highest correlation to the dry weight. Regression analysis with absorbance at 266nm and cell number using a Thoma-Zeiss counting chamber produced the following reliable equation: Y= -252.183+3767.146X (R**2=0.869) Y : Cell no. [l0E4 cell/ml] X : Ab. 266nm
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