Influence of temperature on aerobic granular sludge formation and stability treating municipal wastewater with high nitrogen loadings

This study investigated the influence of temperature (20 and 30 °C) on the formation and stability of aerobic granules in sequential batch reactors (SBR). Therefore, two lab-scale SBRs operated at 20 and 30 °C (SBR₂₀ and SBR₃₀) were used. The reactors were fed with municipal wastewater (COD_t:TN:TP 100:15:1.7), leading to mean organic loading rates (OLR) of 1.3 ± 0.4 kgCOD_t m^-3 day^-1. Both reactors had the same height/diameter ratio of 4.2 and were inoculated with activated sludge from a municipal wastewater treatment plant. The operational conditions were also the same for both temperatures and lasted in stable process parameters for over 100 days. By optimizing the aeration and oxygen concentration, a high removal efficiency of NH₄-N (∼99%) and COD (∼90%) was achieved in both reactors, despite the poor C:N:P ratio at the influent. Furthermore, a relatively low oxygen concentration of 2 mg L^-1 was defined as the set point for the control strategy. Nevertheless, granulation at 30 °C was significantly faster, resulting in more stable sludge volume index (SVI) values (SVI₁₀/SVI₃₀ < 1.1). The granules formed at 30 °C were also larger, more compact, and considerably more stable against system disturbances. However, at higher temperatures, larger granules might be required for nitrate removal because of the increased oxygen diffusion rates. Finally, microbiological 16S rRNA gene amplicon analysis for both systems indicated major differences relatively to the inoculum sludge only for nitrogen-degrading organisms.

Optimisation of the methodology for obtaining enzymatic protein hydrolysates from an industrial grape seed meal residue

The grape pomace industry produces large quantities of protein-rich seeds, which can be a sustainable non-animal protein source; their techno-functional properties could be exploited to improve the colour stabilisation and modulating the astringency of red wines in warm climates. This study aims to optimise the methodology of obtaining protein hydrolysates from defatted grape seed meal residue. Five assays using different quantities of enzyme and raw materials were considered. Based on the protein purity, hydrolysates yield, colour and molecular weight distribution achieved, optimal conditions were the hydrolysis of the alkaline protein concentrate with the highest amount of enzyme. The products obtained showed the lowest colour parameters, with the lightness contributing the most to the colour differences, which were visually perceptible (ΔE*_ab > 3). The hydrophobic amino acids remained within the peptide sequence, leaving polar and charged amino acids in terminal positions, which could affect the wine equilibrium related to colour stabilisation.

Bioenvironmental Trace Elements in Warm Climatic Plant, Pigeon Pea (Cajanus cajan)

Bioenvironmental trace elements play a vital role in plant, animal, and man metabolism. This study aims to determine trace element concentration in different parts (pods, pericarp, seeds, cotyledon, and taste) of the warm climate plant pigeon pea (Cajanus cajan L. Millsp.). The pigeon pea pods were collected from the farms on the shore of the High Dam Lake, Egypt. Elements (Ag, Au, Co, Cr, Sr, Fe, Cu, Ni, Mn, and Zn) in the pods and its different parts were determined by an atomic absorption spectrophotometer. Statistical analysis (cluster, Pearson correlation coefficient, and factor analysis) was applied to trace elements in different parts of pigeon pea. The results reveal that seeds exhibited the highest concentrations of Cu, Ni, Cr, and Zn, while Ag, Co, Pb, and Fe in the pods. Factor and cluster analyses explain a good relationship among the trace elements in pigeon pea. Also, transfer factor of the elements between plant and soil shows that the high transfer factor of most elements was observed for pods and pericarp. The studied elements in the pods and its different parts were in the safety baseline levels for both man and animal uses.

Free ferulic acid supplementation of heat-stressed hair ewe lambs: Oxidative status, feedlot performance, carcass traits and meat quality

Twenty-two Katahdin × Dorper ewe lambs (average weight = 23.5 ± 2.8 kg) were individually housed during a 40-d feeding study and then slaughtered to evaluate effects of free ferulic acid (FA; 0 and 250 mg/kg of feed) on oxidative status, feedlot growth, carcass and non-carcass traits, wholesale cut yields and meat quality under heat stress conditions. Overall feeding FA decreased protein oxidation without affecting oxidative stress index, while growth rate and feed efficiency increased only in the hottest period (i.e., 28 to 45 °C). The FA supplementation increased kidney-pelvic-heart and mesenteric fat deposition, as well as yields of forequarter, shoulder, ribs, loin, and breast and flank, but decreased yields of hindquarter, neck, plain loin and leg. Carcass characteristics and meat quality were unaffected by FA. Overall, FA supplementation of heat-stressed hair ewe lambs enhanced feedlot performance under extreme heat stress and increased internal fat reserves, while changing muscle mass deposition, possibly because it prevented protein oxidation.