Molecular dynamics study on the effects of varying temperature and pressure on phosphatidylcholine lipids for microalgae drying

Abstract

In pursuit of finding a more suitable way of drying microalgae that would require less energy input which will consequently lessen the production cost, a study was conducted to investigate the migration of water molecules across a cell membrane of microalgae. Molecular Dynamics simulations using GROMACS software were utilized to obtain a molecular model of a cell membrane. The membrane model was composed of 32 dilauroylphosphatidylcholine (DLPC) lipids, 32 dioleolyphosphatidylcholine (DOPC) lipids, 32 dipalmitoylphosphatidylcholine (DPPC) lipids, 32 distearoylphosphatidylcholine (DSPC) lipids and 6000 water molecules in an all-atom force field. The effect of varying the temperature on the bilayer thickness and the effect of varying the osmotic pressure on the water migration across the lipid bilayer were determined. The temperature was varied from 300 K to 345 K with 5 K interval and the pressure was changed from 100 MPa to 150 MPa with 10 MPa interval. Results showed that at increasing temperature the bilayer thickness increased but when it reached 340 K the bilayer thickness started thinning. Furthermore, at increasing osmotic pressure the water migration became faster.