No abstract

The full-scale implementation of polyhydroxyalkanoate (PHA) production using mixed microbial cultures (MMCs) has been limited by the low PHA global productivity and overall process yield. This work aimed to demonstrate, at a pilot scale, that by combining different effective operating conditions, it is possible to boost the PHA production performance when using fruit waste as a substrate. The organic loading rate (OLR) and pH of the acidogenic reactor were successfully used as tuning parameters to obtain a high fermentation yield (0.74 gCOD•gCOD −1 ) and a fermentate rich in butyrate, resulting in enhanced PHA production steps. A biomass highly enriched in PHA-storing microorganisms was selected as a result of uncoupling the carbon to the nitrogen feeding. The biomass concentration attained a notable value (7.83 g•L −1 ) as a response to the high OLR (8.7 gCOD•L −1 •d −1 ) imposed. In the PHA accumulation assays, the culture selected at the optimal OLR in the selection reactor achieved a high storage yield (0.98 gCOD•gCOD −1 ), and the continuous feeding strategy led to a maximum PHA content of 80.5% (g-basis). The high global productivity (8.1 g-PHA•L −1 •d −1 ) and overall process yield (0.45 gCOD•gCOD −1 ) are, to the best of the authors' knowledge, the highest values reported for MMC using a real feedstock at pilot scale. These results demonstrate the importance of combining different effective strategies to maximize the process performance, a promising result toward the full-scale implementation of PHA production from wastes and MMC.

No abstract

In this study, we investigate the capability of energy dispersive X-ray fluorescence (EDXF) spectrometry in a triaxial geometry apparatus as a fast and nondestructive determination method of both dominant and contaminant elements in pharmaceutical iron supplements. The following iron supplements brands with their respective active ingredients were analyzed: Neutrofer fólico (iron gylcinate), Anemifer (iron(II) sulfate monohydrate), Noripurum (iron(III)-hydroxide polymaltose complex), Sulferbel (iron(II) sulfate monohydrate), and Combiron Fólico (carbonyl iron). Although we observe a good agreement between the iron content obtained by the present method and that indicated in the supplement's prescribed dose, we observe contamination by manganese and nickel of up to 180 μg and 36 μg, respectively. These contents correspond to 7.2% and 14.4% of the permitted daily exposure of manganese and nickel, respectively, for an average adult individual as determined by the European Medicine Agency (EMEA). The method was successfully validated against the concentrations of several certified reference materials of biological light matrices with similar concentrations of contaminants. Moreover, we also validated our method by comparing the concentrations with those obtained with the inductively coupled plasma-atomic emission technique.