title: Preferential utilization of intracellular nutrients supports microalgal growth under nutrient starvation: multi-nutrient mechanistic model and experimental validation.
abstract: Microalgae are able to grow even under exhaustion of some key nutrients such as nitrogen and phosphorous. Here, we report a multi-nutrient mechanistic model to predict heterotrophic growth of Chlorella sp. FC2 IITG over two sequential phases of fermentation: nutrient sufficient condition to nutrient starved condition. The model assumes that the growth of the microorganism takes place via sequential utilization of extracellular nutrients (ECN) under nutrient replete condition followed by intracellular stored nutrients under exhaustion of limiting nutrients. Further, intracellular nutrient was assumed to be in three different forms: structural form of nutrient (SFN), readily utilizable nutrient (RUN) and non-readily utilizable nutrient (Non-RUN). After the exhaustion of ECN, microorganism switches to RUN followed by Non-RUN to continue its growth, which was experimentally validated by extracting intracellular nitrate and phosphate compounds. The model also incorporates variability in yield coefficients for nitrate and phosphate utilizations.
authors.affiliation: Department of Biotechnology, Indian Institute of Technology, Guwahati, Assam 781039, India.
authors.forename: Basavaraj
authors.initials: B
authors.lastname: Palabhanvi
authors.affiliation: Centre for Energy, Indian Institute of Technology, Guwahati, Assam 781039, India.
authors.forename: Vikram
authors.initials: V
authors.lastname: Kumar
authors.affiliation: Department of Biotechnology, Indian Institute of Technology, Guwahati, Assam 781039, India.
authors.forename: Muthusivaramapandian
authors.initials: M
authors.lastname: Muthuraj
authors.affiliation: Department of Biotechnology, Indian Institute of Technology, Guwahati, Assam 781039, India; Centre for Energy, Indian Institute of Technology, Guwahati, Assam 781039, India. Electronic address: debasishd@iitg.ernet.in.
authors.forename: Debasish
authors.initials: D
authors.lastname: Das
mesh_terms: D058086:Microalgae / Q000254:growth & development* / Q000378:metabolism; D008962:Models, Theoretical
keywords: Intracellular nutrient quota; Mechanistic growth model; Microalgal diauxic growth; Multi-nutrient kinetic model; Variable yield