Enhancing the productivity of biomass, carbohydrates, proteins, and lipids in microalgae cultures is an essential task to justify the feasibility of using biofuels as energetic alternatives to fossil fuels. Diverse strategies can be used to get a biologically plausible optimization of the microalgae culture such as using indigenous microalgae added with other microorganisms such as fungi or bacteria, analyzing the effect of culture broth composition and reaction experimental conditions. A wastewater isolated co-culture microalgae-yeast (CCMY) was evaluated as potential biomass and lipids-efficient producer. The Box-Behnken experimental design and the response surface methodology yield to identify the best attainable composition of inorganic nutrient variables in culture media: sodium nitrate (NaNO₃), potassium phosphate (K₂HPO₄), and ferrous sulfate (FeSO₄). The results of the experimental design revealed that the NaNO₃, K₂HPO₄, and FeSO₄ were three factors significantly influencing the biochemical content. The detected optimal conditions correspond to a highest biomass production of 1.68 g L⁻¹; the carbohydrate content was 16.75%, for proteins 37.11%, and the maximum lipid content was 27.77%. These values were about two times higher than the results obtained with the original version of the culture broth (BBM). The complexity of inorganic salts effect on the biomass and lipid accumulation motivates the proposal of a quartic order mathematical model which characterizes the productivity of microalgae-yeast co-culture as function of the inorganic micronutrient contents.

中文翻译：

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无机微量营养元素下微藻-酵母共培养生物质和代谢产物的同时优化

提高微藻培养物中生物质，碳水化合物，蛋白质和脂质的生产力是证明使用生物燃料作为化石燃料的高能替代品的可行性的一项基本任务。多种策略可用于对微藻培养物进行生物学上的合理优化，例如使用添加有其他微生物（如真菌或细菌）的本地微藻，分析培养液组成和反应实验条件的效果。废水分离共培养微藻酵母（CCMY）被评估为潜在的生物质和脂质高效生产者。Box-Behnken实验设计和响应面方法可确定培养基中无机营养变量的最佳可获得组成：硝酸钠（NaNO ₃），磷酸钾（K ₂ HPO ₄）和硫酸亚铁（FeSO ₄）。实验设计的结果表明，NaNO ₃，K ₂ HPO ₄和FeSO ₄是显着影响生化含量的三个因素。检测到的最佳条件对应于1.68 g L ^-1的最高生物量生产; 碳水化合物含量为16.75％，蛋白质含量为37.11％，最大脂质含量为27.77％。这些值比原始版本的培养液（BBM）获得的结果高大约两倍。无机盐对生物量和脂质积累的复杂影响促使提出了四次数学模型的建议，该模型表征了微藻-酵母共培养的生产力与无机微量营养素含量的关系。