French Associates Institute for Agriculture & Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel.
Appl Microbiol Biotechnol. 2011 May;90(4):1429-41. doi: 10.1007/s00253-011-3170-1. Epub 2011 Mar 23.
We examined responses of batch cultures of the marine microalga Nannochloropsis sp. to combined alterations in salinity (13, 27, and 40 g/l NaCl) and light intensity (170 and 700 μmol photons/m(2)·s). Major growth parameters and lipid productivity (based on total fatty acid determination) were determined in nitrogen-replete and nitrogen-depleted cultures of an initial biomass of 0.8 and 1.4 g/l, respectively. On the nitrogen-replete medium, increases in light intensity and salinity increased the cellular content of dry weight and lipids due to enhanced formation of triacylglycerols (TAG). Maximum average productivity of ca. 410 mg TFA/l/d were obtained at 700 μmol photons/m(2)·s and 40 g/l NaCl within 7 days. Under stressful conditions, content of the major LC-PUFA, eicosapentaenoic acid (EPA), was significantly reduced while TAG reached 25% of biomass. In contrast, lower salinity tended to improve major growth parameters, consistent with less variation in EPA contents. Combined higher salinity and light intensity was detrimental to lipid productivity under nitrogen starvation; biomass TFA content, and lipid productivity amounted for only 33% of DW and ca. 200 mg TFA/l/day, respectively. The highest biomass TFA content (ca. 47% DW) and average lipid productivity of ca. 360 mg TFA/l/day were achieved at 13 g/l NaCl and 700 μmol photons/m(2)·s. Our data further support selecting Nannochloropsis as promising microalgae for biodiesel production. Moreover, appropriate cultivation regimes may render Nannochloropsis microalgae to produce simultaneously major valuable components, EPA, and TAG, while sustaining relatively high biomass growth rates.
我们研究了海洋微藻拟球藻分批培养物对盐度（13、27 和 40 g/l NaCl）和光照强度（170 和 700 μmol 光子/m(2)·s）联合变化的响应。在初始生物量分别为 0.8 和 1.4 g/l 的氮充足和氮缺乏培养物中，测定了主要生长参数和脂质生产力（基于总脂肪酸测定）。在氮充足的培养基中，由于三酰基甘油（TAG）的形成增加，光照强度和盐度的增加提高了细胞干重和脂质的含量。在 7 天内，在 700 μmol 光子/m(2)·s 和 40 g/l NaCl 下，最大平均生产力约为 410 mg TFA/l/d。在胁迫条件下，主要长链多不饱和脂肪酸（EPA）的含量显著降低，而 TAG 达到生物量的 25%。相比之下，低盐度往往会改善主要生长参数，与 EPA 含量的变化较小相一致。在氮饥饿下，较高的盐度和光照强度的组合对脂质生产力不利；生物量 TFA 含量和脂质生产力仅分别为 DW 的 33%和约 200 mg TFA/l/d。在 13 g/l NaCl 和 700 μmol 光子/m(2)·s 下，生物量 TFA 含量（约 47% DW）和平均脂质生产力（约 360 mg TFA/l/d）最高。我们的数据进一步支持将拟球藻作为生产生物柴油的有前途的微藻。此外，适当的培养方案可以使拟球藻同时产生有价值的主要成分 EPA 和 TAG，同时保持相对较高的生物量生长速率。
