The enhanced biomass and lipid accumulation in algae with an integrated treatment strategy by waste molasses and Mg²⁺ addition

ABSTRACT

The effect of Mg²⁺ addition to waste molasses-based medium for algae growth on lipid accumulation and fatty acids profiles was studied. Further, the removal rate of residual metal ions in the culture medium under different concentrations of Mg²⁺ was also explored. When 800 μM Mg²⁺ was added to the medium, the peak values for biomass and lipid productivity were 1.81- and 2.28-times higher than the respective values for non-supplemented medium, exhibited a positive effect on biomass yield and lipid accumulation. The fatty acid profile of algae grown in the optimized medium revealed higher monounsaturated fatty acid levels than that grown in control medium. Furthermore, the biodiesel properties calculated by fatty acid profiles were also discussed. In addition, residual metal ions and nutrient (COD, TN, TP) in waste molasses were efficiency removed upon the addition of Mg²⁺. The results provide a strategy for utilizing magnesium ions as an additive to waste molasses-based medium for algae growth, producing profitable biodiesel and consuming industrial waste.

KEYWORDS:

• Biodiesel
• magnesium ion
• untreated waste molasses
• biomass and lipid accumulation
• metal ion and nutrient removal

Additional information

Funding

This work was funded by the National Natural Science Foundation of China [21666012,21766012];