Effects of fluctuating temperature and silicate supply on the growth, biochemical composition and lipid accumulation of Nitzschia sp

Abstract

Nitzschia sp. (Bacillariophyceae) was grown under temperature and photoperiods mimicking those, typical during summer, spring/fall and winter conditions in the southern United States, and using five silicate (Si) concentrations. In general, higher Si concentrations resulted in higher growth rates in summer and spring/fall conditions and lower organic content. Si-deficient Nitzschia sp. had higher levels of neutral lipid compared to those growing in Si replete media. Under summer conditions, the proportion of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) was relatively stable compared with spring/fall and winter conditions, and the proportion of polyunsaturated fatty acids (PUFA) was low. In the winter condition, SFA and MUFA showed a gradient of decreasing abundance while PUFA gradients increased with increasing Si concentrations in the medium. Cumulative productivity (optimization of growth and lipid content) would be best in the spring/fall but less so in the other conditions for this strain of Nitzschia sp.

Keywords: AFDW; C; DW; FAMEs; GC; Growth; Lipid; MS; MUFA; N; NR; Nile Red; Nitzschia sp.; OD; PUFA; SFA; Seasonal variation; Si; Silicate limitation; ash-free dry weight; carbon; dry weight; fatty acid methyl esters; gas chromatography; mass spectrometer; mono-unsaturated fatty acids; nitrogen; optical density; polyunsaturated fatty acids; saturated fatty acids; silicate.