Front. Mar. Sci.
Sec. Marine Biotechnology and Bioproducts
doi: 10.3389/fmars.2022.983395

Characterization of Pseudochloris wilhelmii potential for oil refinery wastewater remediation and valuable biomass cogeneration

 Maria Blazina1*,  Maja Fafandel1,  Suncana Gecek2,  Ines Haberle2, Jasminka Klanjscek2,  Enis Hrustić1,  Lana Husinec3,  Luka Zilic1, Ena Pritisanac1 and Tin Klanjscek2
  • 1Center for Marine Research, Rudjer Boskovic Institute, Croatia
  • 2Rudjer Boskovic Institute, Croatia
  • 3INA PLC, Croatia
Provisionally accepted:
The final, formatted version of the article will be published soon.

The microalgae of the genus Pseudochloris/Picochlorum are characterized by fast growth, and wide nutrient (type and concentration) and salinity tolerance, all contributing towards exploration of their use in high-density biomass production and wastewater bioremediation. In this study, removal of N and P nutrients from oil refinery wastewater was monitored during growth of the marine eukaryotic microalgae Pseudochloris wilhelmii, with emphasis on biochemical analyses of its biomass quality to evaluate suitability for biodiesel production. A series of growth experiments under various nutrient and light regimes were performed in a temperature range of 20-30ºC to evaluate nutrient removal and biomass growth dependence on temperature. The highest removal rate of dissolved inorganic nitrogen reached under the given experimental conditions was 0.823 mmol/(gday) accompanied by the corresponding biomass productivity of 115.2 mg/(Lday). Depending on light and temperature, the final lipid concentration ranged 181.5 – 319.8 mg/L. Furthermore, increase in nutrient load decreased the maximum specific growth rate, and the maximum specific removal rate of the dissolved inorganic nitrogen. The decrease prolonged the bioremediation process by 2.5 times, with 26% higher maximal specific growth rate and 81% higher maximal biomass production. In contrast, constant light exposure expedited the nitrogen removal, i.e. bioremediation process, by one day, while supporting 60% higher maximal specific growth rate and 100% higher maximal biomass production. The conditions favoring the highest nitrogen removal and highest toxicity reduction in ORWW are met at 24ºC and 130 µmol phot/(m2s). The highest proportion of carbon-binding to the P. wilhelmii biomass was noticed under the same conditions, thus indicating them as the most favorable conditions for hydrocarbon removal as well as for CO2 sequestration. Pseudochloris wilhelmii therefore represents a promising candidate for oil refinery wastewater remediation and valuable biomass cogeneration on a large-scale.

Keywords: Marine micro algae, Pseudochloris wilhelmii, wastewater, Toxicity, phycoremediation, Biodiesel

Received: 01 Jul 2022; Accepted: 02 Sep 2022.

Copyright: © 2022 Blazina, Fafandel, Gecek, Haberle, Klanjscek, Hrustić, Husinec, Zilic, Pritisanac and Klanjscek. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Maria Blazina, Center for Marine Research, Rudjer Boskovic Institute, Zagreb, Croatia