C.J. Zhu, Y.K. Lee-1997
Journal of Applied Phycology, 9 (2) : 189-194 (from Current Contents)
Abstract:
Total biomass dry weight (DW) and ash free dry weight (AFDW) of five species of marine microalgae, Dunaliella sp., Isochrysis galbana, Nannochloropsis sp., Nitzschia closterium and Porphyridium cruentum, retained on filter paper, were determined. Dunaliella and Isochrysis cells have no cell wall; Nannochloropsis, Nitzschia and Porphyridium possess a cell wall and Nitzschia and Porphyridium cells are covered by silica and mucilage coating, respectively. In all these algae, DW of non washed samples was at least 1.2 times higher than those washed by distilled water, 0.9% sodium chloride, 0.5 M ammonium formiate or 0.5 M ammonium bicarbonate. DW of 0.9% sodium chloride washed samples was more than 0.8 times higher than the other three washed samples. In most of the cases, there was no significant difference between DW of samples washed by ammonium formiate and ammonium bicarbonate solutions (p>0.05). The AFDW of the non-washed algal samples was about twice that of washed samples, and could be accounted for by a volatile component in the sea water medium. Isotonic solution of ammonium bicarbonate is a satisfactory washing agent for algal cells for dry weight determination.
(Natl Univ Singapore, Fac Med, Dept Microbiol, Lower Kent Ridge Rd, Singapore 119260, Singapore)