A novel approach in crude enzyme laccase production and application in emerging contaminant bioremediation

Laccase enzyme from white-rot fungi is a potential biocatalyst for the oxidation of emerging contaminants (ECs), such as pesticides, pharmaceuticals and steroid hormones. This study aims to develop a three-step platform to treat ECs: (i) enzyme production, (ii) enzyme concentration and (iii) enzyme application. In the first step, solid culture and liquid culture were compared. The solid culture produced significantly more laccase than the liquid culture (447 vs. 74 μM/min after eight days), demonstrating that white rot fungi thrived on a solid medium. In the second step, the enzyme was concentrated 6.6 times using an ultrafiltration (UF) process, resulting in laccase activity of 2980 μM/min. No enzymatic loss due to filtration and membrane adsorption was observed, suggesting the feasibility of the UF membrane for enzyme concentration. In the third step, concentrated crude enzyme was applied in an enzymatic membrane reactor (EMR) to remove a diverse set of ECs (31 compounds in six groups). The EMR effectively removed of steroid hormones, phytoestrogen, ultraviolet (UV) filters and industrial chemical (above 90%). However, it had low removal of pesticides and pharmaceuticals

A hybrid anaerobic and microalgal membrane reactor for energy and microalgal biomass production from wastewater

In the concept of a circular economy, wastewater is no longer waste but a resource for water, energy and nutrients. In this study, a hybrid system containing an anaerobic membrane bioreactor (AnMBR) and a microalgal membrane reactor (MMR) was developed to harvest energy, nutrients, and microalgal biomass from food and agribusiness industrial wastewater. The AnMBR removed over 97% of chemical oxygen demand (COD) and generated 4.7 ± 0.15 L (n=80) of biogas equivalent to 2.4 kWh kg−1 COD (feed) d −1 . Through anaerobic metabolism, the microorganism in AnMBR generated NH+ 4 and PO3− 4 -rich effluent. Their effluent concentrations were 1.9 and 1.4 times of that in the influent, respectively. NH+ 4 and PO3− 4 -rich effluent was directly used (i.e. without filtration or sterilization) to culture microalgae Chlorella vulgaris in the MMR. . Microalgal biomass production reached up to 700 mg/L after 6 days of operation and nutrient removal rates of above 75% were achieved. However, biomass production and nutrient removal declined towards the end of experiment. The generated biomass was completely harvested using cationic polyacrylamide at the dose of 36 mg g−1 dry weight. Overall, the AnMBR has great potential to produce energy. Future research is needed to intensify the microalgal growth (e.g. genetic modification of strains, addition of plant hormones) in the MMR for continuous operation of the hybrid system