Study of the changes in the growth, protein, and bioactive profile of Chlorella emersonii KJ725233 in response to sodium and ammonium nitrate

Abstract

Chlorella emersonii KJ725233 is a non-fastidious microalga isolated from the western regions of Maharashtra, India. The alterations in its chlorophyll, protein, and antioxidant content in response to cationic stress were studied. Chlorella emersonii KJ725233 (CEK) was subjected to NaNO3 and NH4 (NO3)2 at concentrations equivalent to 0.9 g/l (1×) and 1.8 g/l (2×) in the cultivation media. Qualitative alterations in the bioactives of the microalga were identified by gas chromatography–high-resolution mass spectrometry (GC-HRMS), while the protein, chlorophyll, and antioxidant manipulations were spectrophotometrically quantified. Doubling of the protein content was observed when CEK was grown in 1× NH4+, whereas in 2× NH4+, chlorosis was significant. 2× NH4 + also induced oxidative stress on CEK as evident from the 85.72% ± 6.72%, 197.47% ± 7.01%, 22.24% ± 1.78%, and 187.37% ± 1.88% increase in antioxidant potential, ferric reducing capacity, radical scavenging potential, and total phenolic content, respectively, as compsared to CEK grown in 1× Na+. These alterations as indicated from the GC-HRMS data correlate to the bioactive inductions/variations of/in Vitamin E, phytol, and its isomer in CEK grown in 2× NH4+. The study thus indicates that manipulations of nitrate salts in the media significantly induce, as well as alter the concentrations of commercially significant compounds like Vitamin E, phytol, etc.