Sustainable cultivation of Haematococcus pluvialis and Chromochloris zofingiensis for the production of astaxanthin and co‐products

Abstract

Large-scale cultivation of microalgae for the production of high-value compounds raises concerns on sustainability due to intense consumption of water resources. Use of wastewater for microalgae cultivation is considered a promising alternative, because it not only reduces water consumption, but also provides nutrients required for microalgae growth. In the present study, Haematococcus pluvialis and Chromochloris zofingiensis were cultivated in synthetic dairy wastewater (DWW) to identify the potential of developing highvalue product first biorefineries, with astaxanthin as the main product.H. pluvialis and C. zofingiensis cultivated in DWW achieved biomass concentrations of 0.55 ± 0.01 and 0.65 ± 0.01 g/L, respectively. Astaxanthin contents of 2.1 ± 0.1% and 0.4 ± 0.1% were observed in H. pluvialis and C. zofingiensis grown in DWW. Minimum freshwater consumption for cultivation was 69.93 L/g astaxanthin in control growth media, which could be eliminated by cultivation of microalgae in DWW. COD, TN, and TP removal efficiencies were in the range of 94%-96%, 79%-81%, and 57%-79%, respectively, indicating capability for simultaneous biomass production and phycoremediation. Presence of carbohydrates and lipids in residual biomass suggested the applicability as feedstock for biorefining. Potential avenues to integrate wastewater treatment, astaxanthin production, and valorization of residual biomass were discussed in context of high-value product first biorefineries.

Enhancing the biochemical growth of Haematococcus pluvialis by mitigation of broad-spectrum light stress in wastewater cultures

“… 41 The potential of utilizing synthetic dairy wastewater (DWW) to cultivate H. pluvialis for producing high-value products, particularly astaxanthin, was found to be 2.1 ± 0.1% of 0.55 ± 0.01 g L −1 biomass. 43 …”

“…41 The potential of utilizing synthetic dairy wastewater (DWW) to cultivate H. pluvialis for producing high-value products, particularly astaxanthin, was found to be 2.1 ± 0.1% of 0.55 ± 0.01 g L −1 biomass. 43 3.2.2 Estimation using LC-MS analysis. The total scan chromatogram of H. pluvialis extract was examined using LC-MS/MS.…”

Microbial Carotenoids Production: Strains, Conditions, and Yield Affecting Factors

“…This is because microalgae cells are able to accumulate more carotenoids than bacterial and yeast cells [58]. For example, the microalgae Haematococcus pluvialis can accumulate up to 0.8-4.8 % astaxanthin of dry biomass weight [59], [60], Coelastrella species are capable of producing canthaxanthin up to 4.75-15 % of dry weight [61], [62], and Dunaliella salina up to 6 % β-carotene and 5.4 % lutein simultaneously of the dry weight [63]. Whereas the yeast Phaffia rhodozyma (or teleomorphic state Xanthophyllomyces dendrorhous) generally contains 0.02-0.2 % astaxanthin [64]- [67], Rhodotorula sp.…”