Perfluorooctane sulfonate (PFOS) is one of the most widely distributed environmental pollutants and causes neurotoxicities. Fucoidan is a main bioactive constituent of the brown sea-weed and has many functions in a variety of physiological conditions. The present study attempted to investigate the potential role of fucoidan as neuroprotective marine polypeptide in environmental pollutant-induced apoptosis of neuronal cells in culture. MTT assay showed that cell viability was significantly reduced to 68 % at $30{\mu}M$ PFOS, which was recovered up to 77% and 92% in the presence of fucoidan 25 and $50{\mu}g/ml$, respectively. Cytotoxicity assay showed that LDH release was significantly increased to 160% at $30{\mu}M$ PFOS but was reduced to 150% and 122% in the presence of fucoidan 25 and $50{\mu}g/ml$, respectively. Caspase-3 activity, a hallmark of apoptosis, was measured to determine the cytotoxicity of PFOS and the cytoprotective effects of fucoidan. PFOS induced a 250% increase of caspase-3 activity at $30{\mu}M$ but the increase was dampened to 180% and 130% in the presence of fucoidan 25 and $50{\mu}g/ml$, respectively. PFOS $30{\mu}M$ induced 180 % increase in ROS accumulation, which was effectively blocked by $50{\mu}g/ml$ fucoidan (120% of control). Our results demonstrated that PFOS is a powerful neurotoxicant and fucoidan may be a protective marine bioactive polypeptide against the neurotoxic environmental pollutants. It may contribute to establishing the potential role of fucoidan as a neuroprotective polypeptide that prevents the risk of neurological disorders from the possible neurotoxic pollutants.

Cost-effective microalgae harvesting methods are necessary for economical production of algal biodiesel. In this study, membranes with various pore sizes and materials were examined for their potentials in application to gravity-filtration of Tetraselmis sp. KCTC12432BP. For this test, 10 L of Tetraselmis sp. culture (2 g/L) was loaded on each membrane and filtration rates were measured. Among the tested materials, a woven cotton fabric showed the fastest water drain rate (0.73 L/hr) without serious cell leakage. Cell density of the concentrates after filtration was 6.8 g/L, indicating 3.4-fold concentration compared with the initial algal culture. The result suggests that the woven cotton fabric could serve as filtration membrane for harvesting Tetraselmis sp. among the tested ones.

The purpose of this study was to inhibit biofouling on a selectively permeable membrane (SPM) and increase biomass productivity in marine photobioreactors (PBRs) for microalgal cultivation by chemical treatment. Surfaces of a SPM, composed of polyethylene terephthalate (PET), was sulfonated to decrease hydrophobicity through attaching negatively charged sulfonic groups. Reaction time of sulfonation was varied from 0 min to 60 min. As the reaction time increased, the water contact angle value of SPM surface was decreased from $75.5^{\circ}$ to $44.5^{\circ}$, indicating decrease of surface hydrophobicity. Furthermore, the water permeability of sulfonated SPM was increased from $5.42mL/m^2/s$ to $10.58mL/m^2/s$, which reflects higher nutrients transfer rates through the membranes, due to decreased hydrophobicity. When cultivating Tetraselmis sp. using 100-mL floating PBRs with sulfonated SPMs, biomass productivity was improved by 34% compared with the control group (non-reacted SPMs). In addition, scanning electron microscopic observation of SPMs used for cultivation clearly revealed lower degree of cell attachment on the sulfonated SPMs. These results suggest that sulfornation of a PET SPM could improve microalgal biomass productivity by increasing nutrients transfer rates and inhibiting biofouling by algal cells.