Biofunctionalization of Cork with Moringa oleifera Seeds and Use of PMA Staining and qPCR to Detect Viability of Escherichia coli

Abstract

Cork matrices biofunctionalized with Moringa oleifera seed extracts (MoSe) have potential for use as a biofilter with antibacterial properties to reduce waterborne pathogens. The aim of this study was to evaluate the effect of cork biofunctionalized with active antimicrobial compounds of MoSe (f-cork) on the inhibition of Escherichia coli (InhEc). The LacZ gene from a strain of E. coli was used as the target sequence using viability quantification Polymerase Chain Reaction (qPCR) and differentiation of viable and dead bacteria through selective cell viability PMA staining. To perform this, a 27−4 fractional factorial design and a biofiltration system were used to evaluate the effect of the active protein in MoSe immobilized in granulated cork on InhEc. We found that the potential for antimicrobial activity increased with f-cork for an effective maximal bacterial reduction (99.99%; p < 0.05). The effect of f-cork functionalized with MoSe on E. coli viability was of 0.024% and 0.005% for the cells exposed to PMA, respectively, being the relevant conditions in treatment 2: (0 L/min) without aeration, (5%) MoSe and (5 mm) cork particle. In conclusion, the f-cork functionalized with MoSe presented biosorbent and antibacterial properties that effectively reduced the E. coli growth.