Sze Ying Lee

Aqueous Two-Phase Flotation for the Recovery of Biomolecules

Aqueous two-phase flotation (ATPF), a novel technique which integrates the principles of aqueous two-phase systems and mass transfer mode of solvent sublation, has been successfully applied for the separation and purification of biological materials in the field of biotechnology. From the studies done so far, ATPF has demonstrated as an effective, economical and environment-friendly technique for separation of labile biomolecules from their crude aqueous extracts of natural plants or fermentation broths, under mild separation condition. In this article, the basic principles, experimental apparatus set up, key design variables of ATPF, ATPF applications and a comparative study between ATPF and other conventional methods are discussed. This review is intended to present a comprehensive summary on the research works carried out so far related to ATPF since its introduction in 2009 until present, which will be helpful for further research in ATPF.

Recent Advances in Protein Extraction Using Ionic Liquid-based Aqueous Two-phase Systems

Since its inception in 2003, ionic liquid (IL)-based aqueous two-phase system (ATPS) has been perceived to give a boost to the application of ATPS in protein separation. Given the green and tunable nature of ILs, the functionality of IL-ATPS can be well designed to suit the specificities required by the bioseparation field. Aside from the conventional imidazolium-based ILs, the types of IL investigated have also expanded to other families of cations (e.g., cholinium, ammonium, phosphonium and guanidinium) and benign anions (e.g., carboxylic acids, amino acids and biological buffers). This review aims to provide a comprehensive assessment of the recent literature targeting the applications of IL-ATPSs in the separation and purification of proteins. Different IL families were addressed in terms of their protein-compatibility, and the applicability of the IL-ATPS formed for the separation of a specific protein of interest. Additionally, the present review highlights the possible directions for future developments.

Integration Process of Fermentation and Liquid Biphasic Flotation for Lipase Separation from Burkholderia cepacia

Liquid Biphasic Flotation (LBF) is an advanced recovery method that has been effectively applied for biomolecules extraction. The objective of this investigation is to incorporate the fermentation and extraction process of lipase from Burkholderia cepacia using flotation system. Initial study was conducted to compare the performance of bacteria growth and lipase production using flotation and shaker system. From the results obtained, bacteria shows quicker growth and high lipase yield via flotation system. Integration process for lipase separation was investigated and the result showed high efficiency reaching 92.29% and yield of 95.73%. Upscaling of the flotation system exhibited consistent result with the lab-scale which are 89.53% efficiency and 93.82% yield. The combination of upstream and downstream processes in a single system enables the acceleration of product formation, improves the product yield and facilitates downstream processing. This integration system demonstrated its potential for biomolecules fermentation and separation that possibly open new opportunities for industrial production.

Bioflocculation formation of microalgae-bacteria in enhancing microalgae harvesting and nutrient removal from wastewater effluent

Microalgal bacterial flocs can be a promising approach for microalgae harvesting and wastewater treatment. The present study provides an insight on the bioflocs formation to enhance harvesting of Chlorella vulgaris and the removal of nutrients from seafood wastewater effluent. The results showed that the untreated seafood wastewater was the optimal culture medium for the cultivation and bioflocculation of C. vulgaris, with the flocculating activity of 92.0 ± 6.0%, total suspended solids removal of 93.0 ± 5.5%, and nutrient removal of 88.0 ± 2.2%. The bioflocs collected under this optimal condition contained dry matter of 107.2 ± 5.6 g·L-1 and chlorophyll content of 25.5 ± 0.2 mg·L-1. The results were promising when compared to those obtained from the auto-flocculation process that induced by the addition of calcium chloride and pH adjustment. Additionally, bacteria present in the wastewater aided to promote the formation of bioflocculation process.