Screening for a low-cost Haematococcus pluvialis medium reveals an unexpected impact of a low N/P ratio on vegetative growth

Abstract

Haematococcus pluvialis is the current better source of natural astaxanthin, a high-value carotenoid. Traditionally, the production process of astaxanthin by this algae is achieved by a two-stage system: during the first stage, vegetative "green" cells are produced and then converted, in the second stage, into cysts that accumulate astaxanthin. In this work, a medium screening strategy based on the mixing of a 3-component hydroponic fertilizer was applied to identify a new formulation optimized for the vegetative stage. A maximal and high cell density of 2 x 10 6 cells mL −1 was obtained in a medium containing a high level of phosphate relative to nitrate, resulting in a N:P ratio much lower than commonly used media for H. pluvialis. In this medium, cells remained at the vegetative and motile stage during a prolonged period of time. Both high cell density culture and motile stage persistence was proved to be related to the N:P feature of this medium. We conclude that the macrozoid stage of H. pluvialis is favored under high-P and low-N supply and that low-cost hydroponic fertilizers can be successfully used for achieving high density cultures of vegetative cells of H. pluvialis.

Photosynthesis of Scenedesmus obliquus in outdoor open thin-layer cascade system in high and low CO2 in Belgium

“…This was taken as a indicator for the absence of nutrient limitation. FloraMicro and FloraGro composition can be found in Tocquin et al (2012). In one culture, pH of the medium was stabilized to a value close to 7.5 by injecting pure CO 2 while in the other, pH was not stabilized.…”

Growth of Haematococcus pluvialis Flotow in alternative media

“…However, nitrogen is an essential element for microalgae's growth development, reproduction and other physiological activities (Wang et al, 2013). Ammonium is not only the most preferred nitrogen source for algae, but also the most energetically efficient source, since less energy is required for its uptake (Tocquin et al, 2012). Current results showed that alternative media (NPK and M+NPK) had high nitrogen and phosphorus contents, indicating that they were good tools when only nutrients were needed.…”

“…In fact, current results indicated that high phosphate (2.8 mg.L -1 ) was the key feature leading to beneficial effects on cell growth. Compared to nitrate, phosphate received less attention in optimization approaches although it promoted growth at moderate and low concentrations (Tocquin et al, 2012).…”

A 2015-ös év algája szavazás jelöltjei

“…Az asztaxantin védelmet nyújt az UV károsító hatásával szemben, valamint jelentős gyulladáscsökkentő, ill. immunerősítő hatása van (KOBAYASHI & OKADA 2000). Ez utóbbi magyarázza a széleskörű felhasználási lehetőségeit a humánegészségügy területén is (LORENZ & CYSEWSKI 2000, FÁBREGAS et al 2001, DOMÍNGUEZ-BOCANEGRA et al 2007, CHOI et al 2011, TOCQUIN et al 2012. Az állati takarmányozásban pedig elsődlegesen mint színezőanyagot használják (pl.…”