Effect of microplastics PAN polymer and/or Cu2+ pollution on the growth of Chlorella pyrenoidosa.

Polyacrylonitrile polymer (PAN), a common representative textile material and a microplastic, has significant influence on phytoplankton algae, especially with co-exposure with other pollutants, e.g. Cu2+. In the present study, we carried out experiments to reveal the population size variation trends of Chlorella pyrenoidosa over time (during a whole growth cycle of 6 days) under PAN and/or Cu2+. The levels of pigments (chlorophyll a, b, total chlorophyll and carotenoids), chlorophyll a fluorescence parameters, and other physiological and biochemical indices, containing total protein measurements of H2O2, catalase (CAT), and malondialdehyde (MDA) under different treatment groups were measured to explain the physio-ecological mechanism of the effect of PAN and/or Cu2+ on the growth of C. pyrenoidosa. The results showed that PAN, Cu2+ and the combination of PAN and Cu2+ inhibited the growth of C. pyrenoidosa. Chlorophyll a and b decreased significantly with increasing levels of pollutants (PAN and/or Cu2+); however, the carotenoid levels increased with increasing levels of pollutants (PAN and/or Cu2+) for the first three cultivation days. The oxygen-evolving complexes (OECs) of C. pyrenoidosa had been damaged under Cu2+ pollution. The results also showed that CAT activity, MDA content and H2O2 activity of C. pyrenoidosa increased with increasing levels of pollutants (PAN and/or Cu2+); however, total protein content decreased with increasing levels of pollutants (PAN and/or Cu2+) at the first cultivation day. These results indicate that pollutants (PAN and/or Cu2+) are harmful to the growth of the C. pyrenoidosa population and negatively affect the levels and function of the pigments in C. pyrenoidosa by decreasing chlorophyll a and b levels, increasing carotenoid levels, and increasing antioxidant enzyme activity.

Attachment of marine sponge cells of Hymeniacidon perleve on microcarriers.

Toward the development of an in vitro cultivation of marine sponge cells for sustainable production of bioactive metabolites, the attachment characteristics of marine sponge cells of Hymeniacidon perleve on three types of microcarriers, Hillex, Cytodex 3, and glass beads, were studied. Mixed cell population and enriched cell fractions of specific cell types by Ficoll gradient centrifugation (6%/8%/15%/20%) were also assessed. Cell attachment ratio (defined as the ratio of cells attached on microcarrier to the total number of cells in the culture) on glass beads is much higher than that on Cytodex 3 and Hillex for both mixed cell population and cell fraction at Ficoll 15-20% interface. The highest attachment ratio of 41% was obtained for the cell fraction at Ficoll 15-20% interface on glass beads, which was significantly higher than that of a mixed cell population (18%). The attachment kinetics on glass beads indicated that the attachment was completed within 1 h. Cell attachment ratio decreases with increase in cell-to-microcarrier ratio (3-30 cells/bead) and pH (7.6-9.0). The addition of serum and BSA (bovine serum albumin) reduced the cell attachment on glass beads.