Continuous recovery and enhanced yields of volatile fatty acids from a continually-fed 100 L food waste bioreactor by filtration and electrodialysis.

A novel method to recover VFAs from a continually-fed 100 L food waste bioreactor was developed using industrially applicable methods. The in-situ recovery of VFAs increased production rates from 4 to 35 mgvfa gvs-1 day-1 by alleviating end-product inhibition and arresting methanogenesis, and electrodialysis was able to concentrate the recovered VFAs to 4000 mg L-1. There remains considerable scope to increase the production rates and concentrations further, and the VFAs were recovered in a form that made them suitable for use as platform chemicals with minimal refining. This is the first time that continuous VFA recovery from real-world food waste has been reported at this scale with continual feeding, and represents a promising means through which to produce sustainable platform chemicals. Furthermore the production of VFAs arrests methane production in bioreactors, which is a low value product around which there is a growing concern about fugitive emissions contributing to climate change.

A new sequential injection analysis-capillary electrophoresis system with amperometric detection.

A novel and fully automated sequential injection analysis manifold coupled to a capillary electrophoresis apparatus with amperometric detection, is described. The sequential injection manifold was isolated from the high voltage by inserting an air plug into the circuit. Small buffer reservoirs were used to avoid the need to pump fresh buffer to the interface during the electrophoretic separation. No decoupling device was used to mitigate the interference from the high voltage electric field, instead the potential shift induced by the separation voltage, was accounted for. The new hydrodynamic injection method presented is based on the overpressure created in the circuit when a pinch valve is closed for a predetermined time. The injection method yields RSD values of peak height and area below 2.55 and 1.82%, respectively, at different durations of valve closure (n = 5). The capillary and working electrode alignment was achieved by adapting a commercial available capillary union. When the electrode was replaced, the alignment method proved to be very reliable, yielding RSD values of peak height and area lower than 2.64 and 2.08%, respectively (n = 8). Using this system with a gold microelectrode, dopamine, and epinephrine could be quantified within the concentration range of 1-500 µM and detected at a concentration of 0.3 µM. The methods here presented could be applied for the development of new capillary electrophoresis systems with amperometric detection and/or to the design of fully automated systems for online process monitoring purposes.