Picochlorum sp. strain SENEW3 is a halotolerant green alga with high growth rates and the ability to utilize organic nitrogen sources including wastewater generated from hydrothermal liquefaction (HTL-WW). Picochlorum acclimates to the presence of HTL-WW. In a photosynthesis/respiration rate test, Picochlorum SENEW3 showed a stress response to HTL-WW additions in a dose-dependent manner while cells pre-grown with HTL-WW had a greatly reduced response to additions. A quantitative proteomics tool, iTRAQ, was applied to assess Picochlorum global proteome changes in response to HTL-WW as a nitrogen source. From this approach, a total of 350 different proteins were identified across 2 biological replicates which were significantly up-regulated or down-regulated (average ratio of more than 1.2 or less than 0.8, at least one p-value of < 0.05). Protease and oxidative stress enzymes were notably up-regulated. An aminopeptidase enzyme assay showed that, compared to controls, cells grown with 0.1% (vol) HTL-WW had 2.1-fold higher protease activity. An ascorbate peroxidase assay showed an 8.6-fold increase in exponential cells grown with 0.1% HTL-WW compared to controls. This study provides insights into the development of microalgae for algal biofuel production using HTL wastewater recycling .
Wang, S., Shi, X., & Palenik, B. (2016). Characterization of Picochlorum sp. use of wastewater generated from hydrothermal liquefaction as a nitrogen source. Algal Research, 13, 311–317. https://doi.org/10.1016/j.algal.2015.11.015