Enzymatic quorum quenching for enhanced production of microalgae biomass in membrane-based floating photobioreactor

초록

Microalgae are promising sustainable biomass sources for various bioprocesses. In microalgae cultivation systems, floating photobioreactors with semi-permeable membranes (SPM-PBRs) can sustainably supply nutrients and energy; however, membrane biofouling significantly reduces biomass productivity. In this study, a quorumquenching nanobiocatalyst was integrated into SPM-PBRs to mitigate biofouling during microalgae cultivation. The quorum-quenching acylase (AC) enzyme was stabilized by adsorption onto carbon nanotubes (CNTs), and the resulting composites were immobilized onto the SPM surface via polydopamine (pDA) coating. The ACfunctionalized SPMs exhibited a lower water contact angle (50.40 degrees) compared to bare SPM (102.45 degrees) and pDA-SPM (63.84 degrees). After 5 days of batch cultivation in natural seawater, PBRs equipped with AC-functionalized SPMs showed minimal losses in both water and nitrate permeabilities, as well as the lowest membrane weight gain, resulting in a 2.2-fold increase in biomass productivity during a single cultivation cycle. Moreover, the ACfunctionalized SPMs maintained this enhanced productivity across four consecutive cultivation cycles, demonstrating their potential for long-term operation in marine environments.

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