Optimization of peptide production by enzymatic hydrolysis of tuna dark muscle by-product using commercial proteases

A protein hydrolysate was prepared from proteins of tuna dark muscle by-product. The hydrolysis conditions (time, temperature, pH and enzyme concentration) using Alcalase and Neutrase were optimized by response surface methodology (RSM). The regression coefficient close to 1.0, observed during experimental and validation runs, indicated the validity of the model. The hydrolysate produced under the optimum conditions determined by RSM using Alcalase, had a low rate of peptide fraction of molecular weight of 1-4 kDa. Meanwhile, the results obtained by hydrolysis under optimal conditions determined by a complementary study (temperature 55°C, time 60 min, 1% enzyme concentration and pH 8.5) show that the hydrolysate produced had a high rate of the peptide fraction of molecular weight of 1-4 kDa. The amino acid composition of the protein hydrolysate prepared proved to have the potential for application as an ingredient in balanced fish diets and as a source of nitrogen in microbial growth media.Keywords: Alcalase, neutrase, tuna dark muscle, RSM, optimization, protein hydrolysate, peptides, degree of hydrolysisAfrican Journal of Biotechnology Vol. 12(13), pp. 1533-154

Optimal design of industrial scale continuous process for fractionation by membrane technologies of protein hydrolysate derived from fish wastes

The fractionation in an industrial-scale continuous process of a protein hydrolysate obtained from tuna wastes has been proposed. A model based on membrane transport equations, mass balances and economic equations to calculate the main costs of the process was developed. This model was applied to the evaluation of the main technical, environmental and economic aspects of the process and their optimization. The basic cascade configuration resulted better than alternative options like the linear or dual cascades. The freshwater consumption was minimized to improve the environmental and economic performance of the process. Indeed, the implementation of a water recovery and reuse system was the most effective solution. This system was based on the installation of an additional tight nanofiltration stage that reduced the environmental impact of the process (avoiding the need of auxiliary freshwater streams) and increased its economic competitiveness.This project has received financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) through CTQ2014-56820-JIN Project, co-financed by FEDER funds

Water recovery and reuse in the fractionation of protein hydrolysate by ultrafiltration and nanofiltration membranes

The fractionation of a protein hydrolysate obtained from tuna processing by-products by means of a membrane cascade integrating ultrafiltration (UF) and nanofiltration (NF) membranes was proposed in order to separate and purify the protein fraction between 1 and 4 kDa, which is the most interesting for nutraceutical purposes. A simulation model, based on mass balances and empirical equations for describing permeate flux and rejection of protein fractions, was developed and complemented with a simple cost estimation model. The product purity (49.3 %) and the process yield (62.6 %) were independent of the total water consumption of the process, but high water consumptions were required to maintain the total protein content of the stream below upper bounds that assured the absence of membrane clogging. The implementation of a water recovery system, based on an additional tight NF stage, implied improvements in both environmental and economic aspects of the process

Erythromycin degradation by an esterase in enzymatic membrane reactors

1 Introduction Pharmaceuticals products (PPs) and endocrine disrupting chemicals (EDCs) as well as their transformation products have been detected in almost all effluents from sewage facilities, in surface water, in groundwater, adsorbed on sediments and even in drinking water [1,2]. Ecotoxicity studies have demonstrated that pharmaceutical pollutants could affect the growth, reproduction and behavior of birds, fishes, invertebrates, plants and bacteria [3,4]. Some recently published studies report that the presence of low concentrations of antibiotics in the wastewaters may develop antibiotic resistance in the whole environment [5, 6]. As previously reported by Demarche et al. [7], the use of enzymes might be beneficial to enhance or complement conventional wastewater treatments. As far as enzymes are relatively expensive the reuse of the biocatalyst appears to be essential to ensure the economic and industrial viability of the process. Enzymatic membrane reactors appear to be an interesting alternative since they enable to couple reaction and separation [8]. In fact, in such enzymatic reactors, the substrate is continuously brought in contact with the biocatalyst, which is retained by the membrane, either freely circulating with the retentate or fixed on or within the membrane and the reaction products are recovered in the permeate. This work describes the study of erythromycin degradation by an EreB esterase in free and immobilized forms. It focuses on the comparison between 3 different enzymatic membrane reactors for erythromycin degradation by esterase EreB. In the first configuration the free biocatalyst was confined in the reaction media by a ceramic membrane. In the two other cases, the enzyme was immobilized in the membrane either covalently grafted or adsorbed. Please click Additional Files below to see the full abstract

Associations between circulating cardiovascular disease risk factors and cognitive performance in cognitively healthy older adults from the NuAge study

IntroductionCardiovascular disease risk factors (CVRFs) contribute to the development of cognitive impairment and dementia.MethodsThis study examined the associations between circulating CVRF biomarkers and cognition in 386 cognitively healthy older adults (mean age = 78 ± 4 years, 53% females) selected from the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge). Memory, executive function, and processing speed were assessed at baseline and 2-year follow-up. CVRF biomarkers included total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides, glucose, insulin, high sensitivity C-reactive protein (hs-CRP), homocysteine, protein carbonyls, and cortisol. Linear mixed models were used to determine associations between individual CVRF biomarkers and cognition at both time points.ResultsHDL-C was most consistently associated with cognition with higher values related to better performance across several domains. Overall, stronger and more consistent relationships between CVRF biomarkers and cognition were observed in females relative to males.DiscussionFindings suggest that increases in the majority of circulating CVRFs are not associated with worse cognition in cognitively healthy older adults

Etude du colmatage d'une membrane minerale de microfiltration tangentielle par les constituants macromoleculaires du vin

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 78997 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Étude d'un réacteur enzymatique à membrane (application à la synthèse de butyl laurate)

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Caractérisation du fruit de noni (Morinda citrifolia) au cours du processus de maturation et de sénescence et étude de l'impact de la microfiltration tangentielle sur la composition du jus

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF