Evaluation of Cell-Viability, Intracellular Lipid-Component and Efficiency of Lipid-Extraction of Chlamydomonas reinhardtii Cells Treated by UV-C Irradiation Aiming to Use Cell Directly
Aim: We aimed finally to construct a system to utilize intracellular lipids of Chlamydomonas reinhardtii by direct cell-use. To realize the system, a system of simple cell-sterilization to avoid environmental contamination without degradation of intracellular lipids was required. Industrially, a simple collecting system of internal lipids was also required. Methods and results: C. reinhardtii cultured in a photo bioreactor under autotrophic condition was irradiated by UV-C. After the irradiation with different time to cells under different culturing conditions, those cells were evaluated for cell-viability by staining with neutral red, intracellular cell components and efficiency of lipid-extraction with GC/FID, respectively. By UV-C irradiation for 10 min, C. reinhardtii cells after N-depletion were sterilized. Additionally, although the cells were morphologically crumbled under an optical microscope, the contents and the components of intracellular lipids showed few differences. Conclusion: C. reinhardtii cells were efficiently sterilized by UV-C irradiation and few treated cells leaked the intracellular lipids, indicating that the lipids could not be simply collected by centrifuging direct cell collection. Significance and impact of study: In this study, the sterilized cells could gradually leak the intracellular contents, indicating the possibility of direct-use of the cells to utilize lipids produced by C. reinhardtii.