An effective, cost-efficient extraction method of biomass from wet microalgae with a functional polymeric membrane

Abstract

For energy-efficient extraction of biomass from microalgae, it is essential to extract the intracellular lipid directly from wet microalgae without drying the microalgal biomass. In this work, a novel, highly efficient cell disruption process was devised using a functional membrane coated with a cationic polymer. The proposed mechanism of cell disruption involves the perturbation of the local electrostatic equilibrium of the amphiphilic microalgal cell membrane caused by the direct contact with the tertiary-amine cations on the surface of the membrane. A tert-amine-containing polymer, poly-dimethylaminomethylstyrene (pDMAMS) film was conformally deposited on a nylon membrane by a vapor-phase polymerization process, termed as initiated chemical vapor deposition (iCVD). For the wet extraction with this membrane, the pDMAMS-coated membrane was immersed in a microalgal culture of Aurantiochytrium sp. KRS101. The microalgal culture was simply shaken together with the membrane to prompt the contact with the pDMAMS-coated membrane. With this ultimately simple procedure, the bursting of cells was clearly observed. Surprisingly, by this simple, energy-efficient process, a significantly high disruption yield of 25.6 ± 2.18% was achieved. The membrane-based extraction process is highly desirable in that (1) the process does not require an energy-consuming drying procedure, and (2) the proposed cell disruption method with a functional membrane is extremely simple and highly efficient.