BACKGROUND: Immobilized cultivation of microorganisms is gaining interest in the microalgae industry. In this study, a novel microalgae polymeric carrier, sodium cellulose sulphate/poly-dimethyl-diallyl-ammonium chloride (NaCS-PDMDAAC) capsule system, was employed to immobilize Chlorella sp. Microalgae cultivation was performed under immobilized and suspended conditions, and the resulting cells were characterized biochemically and physically.

RESULTS: Experimental results indicated that microalgae cells cultivated under NaCS-PDMDAAC immobilized conditions have a robust morphology, a smaller average cell size of 2.92 µm and a higher Zeta potential of − 17.10 mV than the suspended cells with a cell size of 6.81 µm and Zeta potential of − 32.90 mV. The immobilized microalgae cells displayed a total lipid content of 14.85%, and a chlorophyll content of 3.36%, slightly higher than those obtained from the suspended cells.

CONCLUSION: These differences are critical to further explore the impact of immobilized microalgae cultivation systems for specific biotechnological applications. © 2012 Society of Chemical Industry

BACKGROUND: Microalgae continue to be a focus of industrial bioprocess sustainability practice owing to the numerous biofuels and bioproducts that can be obtained with simultaneous environmental bioremediation applications. However, the extremely dilute nature of large volume microalgal cultures and the small particle size of single-cell microalgae present technological and economic problems of effective dewatering, thus affecting the application of microalgae in process industries. Microalgae immobilization using biocompatible polymeric systems has proved to be an effective strategy to circumvent the heavy dewatering requirement, as this approach provides physical separation between the solid microalgal cells and the liquid medium.

RESULTS: In this work, a novel microalgae immobilization carrier, sodium cellulose sulphate/poly-dimethyl-diallyl-ammonium chloride (NaCS-PDMDAAC) capsule, was synthesized and the resulting polymeric capsules were characterized using physicochemical techniques such as Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM-EDX) and nuclear magnetic resonance spectroscopy (NMR). Experimental results showed that the unique properties of NaCS-PDMDAAC capsules, such as pore size, capsule size, mechanical strength, and structural and compositional homogeneity, relevant to microalgae cultivation with batch or continuous nutrient removal can be accurately controlled.

CONCLUSION: These polymeric capsules find applications not only with microalgae cultivation but also for other microorganisms. © 2012 Society of Chemical Industry

This paper reviewed the mass-transfer of the target substance in the biofilm-covered granular activated carbon (BGAC) system. Representative hypotheses and equations related to developing the mathematical models for a BGAC reactor were discussed in terms of granular activated carbon (GAC) phase, biofilm phase and bulk solution, respectively. It should be noted that discrete phenomena such as biofilm detachment due to erosion or sloughing were not considered for the modeling system. Recent advances on this topic were thoroughly updated, as well as those models proposed in past decades. It appears that a general BGAC model has not been available so far, and further efforts are required to obtain models more approaching of the physical mechanism of this complicate system. Copyright © 2012 Society of Chemical Industry