Effect of nitrate on oil content and fatty acid composition of Nannochloropsis sp. at early stationary growth phase

Fong Lee Ng, . and Thye San Cha, . and Aziz Ahmad, . and Saw Hong Loh, . Effect of nitrate on oil content and fatty acid composition of Nannochloropsis sp. at early stationary growth phase. pp. 30-36. ISSN 1823-8556

A study was conducted to investigate the effect of different nitrate concentration (0.03 0.05 0.09 0.18 0.18 0.34 and 0.66 mM) on oil content and fatty acid composition of Nannochloropsis sp. (strain UMT-M3) at early stationary growth phase. Results showed that the biomass production increased approximately 7-folds at 0.34 and 0.66 mM nitrate (p0.05) which produced between 0.63 to 0.78 g/L of cells dry weight. The highest oil content 0f 13.3 (dry weight basis) was obtained at 0.34 mM nitrate. The analysis of oil revelaed that palmitic (C16:0) stearic (C18:0) oleic (C18;1) linoleic (C18:2) gamma-linolenic (C18:3n6) and alpha linolenic (C18:3n3) acids were the major type of fatty acids detected in all nitrate treatments. Interestingy the accumulation pattern for C16:0 was completely in reverse of C18:2 and C18:3n3 in nitrate ranging from 0.03 to 0.18 mM. The most critical regulatory point occured at 0.05 mM nitrate where the highest (p0.05) accumulation of C16:0 (40.6) was at the expense of C18:2 (11.4). Surprisingly the content of C18:1 (31.0 - 35.0) was unaffected in all nitrate concentrations. These observations lead to the postulation that the activities of genes such as 12 an 15-desaturase that regulate the synthesis of C18:2 and C18:3n3 are concerted in actions and are in reverse of palmitoyl-ACP thioesterase gene which regulated the synthesis of C16:0.

Full text available from: Official URL: http://jssm.umt.edu.my/files/2012/05/Effect-of-nit...

Abstract

A study was conducted to investigate the effect of different nitrate concentration (0.03 0.05 0.09 0.18 0.18 0.34 and 0.66 mM) on oil content and fatty acid composition of Nannochloropsis sp. (strain UMT-M3) at early stationary growth phase. Results showed that the biomass production increased approximately 7-folds at 0.34 and 0.66 mM nitrate (p0.05) which produced between 0.63 to 0.78 g/L of cells dry weight. The highest oil content 0f 13.3 (dry weight basis) was obtained at 0.34 mM nitrate. The analysis of oil revelaed that palmitic (C16:0) stearic (C18:0) oleic (C18;1) linoleic (C18:2) gamma-linolenic (C18:3n6) and alpha linolenic (C18:3n3) acids were the major type of fatty acids detected in all nitrate treatments. Interestingy the accumulation pattern for C16:0 was completely in reverse of C18:2 and C18:3n3 in nitrate ranging from 0.03 to 0.18 mM. The most critical regulatory point occured at 0.05 mM nitrate where the highest (p0.05) accumulation of C16:0 (40.6) was at the expense of C18:2 (11.4). Surprisingly the content of C18:1 (31.0 - 35.0) was unaffected in all nitrate concentrations. These observations lead to the postulation that the activities of genes such as 12 an 15-desaturase that regulate the synthesis of C18:2 and C18:3n3 are concerted in actions and are in reverse of palmitoyl-ACP thioesterase gene which regulated the synthesis of C16:0.

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Item Type:	Article
AGROVOC Term:	Algae
AGROVOC Term:	Aquatic plants
AGROVOC Term:	Fatty acids
AGROVOC Term:	Extraction
AGROVOC Term:	Flocculation
AGROVOC Term:	Analysis of variance
AGROVOC Term:	Genes
AGROVOC Term:	Cell elongation
AGROVOC Term:	Biosynthesis
AGROVOC Term:	Growth
Depositing User:	Mr. AFANDI ABDUL MALEK
Last Modified:	24 Apr 2025 00:54
URI:	http://webagris.upm.edu.my/id/eprint/8732

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