Polyphosphate (Poly-P) accumulation has been reported in Chlorella vulgaris under
nitrogen deficiency conditions with sufficient P supply, and the process has been demonstrated to have great impact on
lipid productivity. In this article, the utilization of
polyphosphates and the regreening process under N resupplying conditions, especially for
lipid production reviving, were investigated. This regreening process was completed within approximately 3-5 days.
Polyphosphates were first degraded within 3 days in the regreening process, with and without an external P supply, and the degradation preceded the assimilation of
phosphate in the media with an external P offering.
Nitrate assimilation was markedly influenced by the
starvation of P after
polyphosphates were exhausted in the medium without external
phosphates, and then the reviving process of biomass and
lipid production was strictly impeded. It is, thus, reasonable to assume that simultaneous provision of external N and P is essential for overall
biodiesel production revival during the regreening process.