Determination Of Essential Amino Acids Research Articles

Engineering Yarrowia lipolytica to Simultaneously Produce Lipase and Single Cell Protein from Agro-industrial Wastes for Feed

Lipases are scarcely exploited as feed enzymes in hydrolysis of lipids for increasing energy supply and improving nutrient use efficiency. In this work, we performed homologous overexpression, in vitro characterization and in vivo assessment of a lipase from the yeast Yarrowia lipolytica for feed purpose. Simultaneously, a large amount of yeast cell biomass was produced, for use as single cell protein, a potential protein-rich feed resource. Three kinds of low cost agro-industrial wastes were tested as substrates for simultaneous production of lipase and single cell protein (SCP) as feed additives: sugarcane molasses, waste cooking oil and crude glycerol from biodiesel production. Sugarcane molasses appeared as the most effective cheap medium, allowing production of 16420 U/ml of lipase and 151.2 g/L of single cell protein at 10 liter fermentation scale. In vitro characterization by mimicking a gastro-intestinal environment and determination of essential amino acids of the SCP, and in vivo oral feeding test on fish all revealed that lipase, SCP and their combination were excellent feed additives. Such simultaneous production of this lipase and SCP could address two main concerns of feed industry, poor utilization of lipid and shortage of protein resource at the same time.

Application of NIR transmission spectroscopy with effective wavelength selection in non-destructive determination of essential amino acid content of foxtail millet

The near infrared (NIR) spectroscopy models developed for rapid and accurate determination of nine essential amino acids and protein in foxtail millet were investigated. The effects of the status of the samples (intact or ground), amino acid/protein correlation and variable selection methods on the predictive ability of the models were analysed. According to results, although the average spectral patterns of the intact and ground samples were similar, the absolute values of peaks and valleys for the intact samples were slightly higher. The modelling results of intact samples were similar to those obtained with ground samples. In the results of the partial least squares models with full spectra, 81-94% of the amino acid variance could be explained, except for lysine, tryptophan and methionine with the coefficients of determination of cross-validation less than 0.70. The correlation between various amino acids and protein might affect the predictive ability of NIR spectroscopy for essential amino acids. After variable selection, the models for isoleucine, leucine, phenylalanine, threonine, tryptophan and valine were remarkably improved by the successive projections algorithm method. The results indicated that short-wave NIR spectroscopy coupled with variable selection is a promising approach for determination of essential amino acids in foxtail millet.

Determination of Essential Amino Acids in Pangasius bocourti

The purpose of this research was to analyze for the determination of essential amino acid in Pangasius bocourti which was aged between1-12 months. Essential amino acid were extracting by 6 M hydrochloric acid (HCl) using the EZ-Fast technology technique and afterwards the quality and quantity was analyzed by using the GC-MS. The highest amounts of essential amino acid were found in Pangasius bocourti aged 1 month. The highest quantities of essential amino acids were Lysine 8.41% and Leucine 8.30%. Other essential amino acid such as Phenylalanine, Methionine, Isoleucine and Tryptophan were found at 4.54%, 4.35%, 4.25% and 2.36% respectively. In month 9, Threonine and Histidine were found at the highest amounts of essential amino acid, this was 5.85% and 2.96%, respectively. Valine had the highest amounts at 7 months and 15 days for 6.79%.

Determination of essential amino acids in human serum by a targeting method based on automated SPE–LC–MS/MS: Discrimination between artherosclerotic patients

An automated method based on a hyphenated SPE-LC-MS/MS configuration has been optimized for the determination of essential amino acids (threonine, valine, methionine, leucine, isoleucine, lysine, tryptophan, and phenylalanine) in human serum, with the aim of discriminating between different states of coronary artery disease. Validation in terms of sensitivity (detection limits below 28.0 ng on column) and precision (repeatability expressed as relative standard deviation below 6.0%) supports the suitability of the method for application to a cohort of 122 atherosclerosis patients confirmed by a catheterization test. The cohort was composed by 80 individuals diagnosed with stable angina and 42 patients who suffered from acute myocardial infarction (AMI). Both groups of individuals are differentiated by the occurrence of ischemia in AMI patients due to the formation of thrombi. The chemometric treatment of the data obtained by multivariate analysis of variance (MANOVA) allowed comparison between both groups of diagnosed patients. Therefore, amino acids whose serum levels were affected by ischemia have been identified. The contribution of risk factors such as obesity and hypercholesterolemia as well as the individuals' gender to the concentration of essential amino acids has also been studied.

Axenic culture of Tyrophagus putrescentiae in a chemically deffined diet and determination of essential amino acids

A chemically defined axenic diet has been formulated for the acarid mite, Tyrophagus putrescentiae. With the use of this diet, the essentiality or non-essentiality of amino acids for the species was determined by the indirect method using glucose-UL 14C in the diet and also by deletion of some individual amino acids from the diet. Essential amino acids were threonine, valine, methionine, leucine, isoleucine, phenylalanine, tyrosine, tryptophan, lysine, arginine, and histidine, the classical ten amino acids essential in the nutrition of the rat.

Determination of essential amino-acids in some Ceylon vegetables.

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