Fourier Transform Infrared Spectroscopy for Assessing Structural and Enzymatic Reactivity Changes Induced during Feather Hydrolysis.

Chicken feathers are major byproducts of the livestock processing industry with high potential in the feed sector. In this study, we present a new approach using Fourier transform infrared (FTIR) spectroscopy to detect the structural changes of feather keratin and its availability for enzymatic hydrolysis (AEH) induced by the thermal pressure hydrolysis (TPH) process. Compared to time-consuming in vitro measurement techniques, the proposed method provides rapid information about the structural changes during TPH which enables quick adaptation of TPH conditions as the quality of the incoming feather changes. By analyzing the FTIR spectra of raw and processed feathers, it was found that AEH negatively relates to the ß-sheet content (represented by two IR peaks centered at 1635 and 1689 cm-1), while it positively relates to a new series of peaks centered around 1700 cm-1 appearing after the TPH process. The proposed FTIR technique provides a reliable and rapid approach to determine the digestibility indicated by AEH of the processed feather and may be used in process control and optimization.

A plant wide simulation of polyhydroxyalkanoate production from wastewater and its conversion to methyl crotonate.

This work simulates the production of methyl crotonate from various industrial wastewaters. In the upstream process, wastewater is fermented into volatile fatty acids which are then converted into polyhydroxyalkanoates (PHA) by means of mixed microbial cultures. In the downstream, PHA undergoes a series of thermolysis and esterification reactions to produce methyl crotonate. The origin of the wastewater was found to have a great influence on the composition of the PHA with the effluent of a candy bar factory producing a high polyhydroxybutyrate/polyhydroxyvalerate ratio of 86/14 in favour of methyl crotonate production. It was observed that the use of intracellular polyhydroxybutyrate, instead of purified, significantly lowers the number of separation steps and yet reduces the methyl crotonate recovery by only 20 %. An operating pressure higher than 18 bar led to more transesterification of polyhydroxybutyrate, producing byproducts instead of methyl crotonate. Finally, a 3 h reaction was found sufficient for completion of polyhydroxybutyrate conversion.

Development of Thin-Film Composite Membranes for Nanofiltration at Extreme pH.

Water recycling is one of the most sustainable solutions to growing water scarcity challenges. However, wastewaters usually contain organic pollutants and often are at extreme pH, which complicates the treatment of these streams with conventional membranes. In this work, we report the synthesis of a robust membrane material that can withstand prolonged exposure to extreme pH (of 1 or 13 for 2 months). Polyamine thin film composite (TFC) membranes are prepared in situ by interfacial polymerization between 1,3,5-tris(bromomethyl)benzene (tBrMeB) and p-phenylenediamine (PPD). Contrary to conventional polyamide TFC membranes, enhanced pH stability is achieved by eliminating the carbonyl groups from the polymer network. The membranes showed pure water permeance and molecular weight cutoff (MWCO) of 0.28 ± 0.09 L m-2 h-2 bar-1 and 820 ± 132 g mol-1, respectively. The membrane performance is further enhanced by manipulating the monomer structures and replacing p-phenylenediamine with m-phenylenediamine, resulting in a higher permeance of 1.3 ± 0.3 L m-2 h-1 bar-1 and a lower MWCO of 566 ± 43 g mol-1. Given the ease of fabrication and excellent stability, this chemistry represents a step forward in the fabrication of robust membranes for industrial wastewater recycling.