Yield Of Amino Acids Research Articles

In situ extraction and enrichment of multiple amino acids by integrated mechanochemical extraction and aqueous two-phase system

A highly efficient and environment-friendly extraction technology was established to extract and enrich multiple amino acids (AAs) in situ by deep eutectic solvent (DES)-assisted mechanochemical extraction (MCE) and aqueous two-phase system (ATPS). Firstly, the DES was prepared from betaine and ethylene glycol in a 1:2 M ratio. Then, a series of conditions were evaluated by single-factor and multifactor experiments to select the optimum experimental parameters. The highest extraction yields of AAs were obtained by DES-assisted MCE and ATPS enrichment, including that the amount of DES was 0.97 mL, the milling time was 4.88 min, the amount of salt was 8 g, and the solid-to-liquid ratio was 0.055 g mL−1. After extracting, the diluted AA extracts were analyzed by a high-performance liquid chromatography-fluorescence detector after pre-column derivatization with 6-aminoquinolyl-N-hydroxysccinimidyl carbamate. The methodological validation demonstrated the proposed method exhibited satisfactory limits of detection ranged from 0.11 to 0.82 ng mL−1, reliable interday precision (%RSD) of 0.014–0.067 % for retention time and 1.29–3.34 % for the peak area, acceptable reproducibility with %RSD below 4.1 %, and good %recovery between 90.3 % and 122.5 % at three spiked concentrations. The surface morphology of raw, only ground, and DES-ground sample powders was tested by scanning electron microscopy to further explore the changes in the physicochemical properties of samples. By comparing with other AAs extraction methods, the developed method is not only eco-friendly, but greatly improves the yield of free AAs extracted from chrysanthemum.

Influence of yeast growth conditions and proteolytic enzymes on the amino acid profiles of yeast hydrolysates: Implications for taste and nutrition

This study investigated the effects of aerobic and anaerobic growth and proteolytic enzymes on the amino acid content of yeast hydrolysates in relation to taste and nutrition. Saccharomyces cerevisiae ATCC5574 was grown under fed-batch aerobic or batch anaerobic conditions. Intracellular glutamic acid (Glu) concentrations were 18-fold higher in aerobic yeast.Hydrolysis with papain and alkaline protease released more amino acids (AA) than simple autolysis or hydrolysis with bromelain, most significantly when applied to aerobic yeast (∼2-fold increase). Autolysates and bromelain hydrolysates from aerobic yeast had low levels of bitter and essential AAs, with high levels of umami Glu. Papain and alkaline protease hydrolysates of aerobic yeast had high levels of umami, bitter and essential AAs. Autolysates/hydrolysates from anaerobic yeast had moderate, high, and low levels of bitter, essential and umami AAs.Selection of both yeast growth conditions and hydrolysis enzyme can manipulate the free AA profile and yield of hydrolysates.

Amino acids foliar spraying palliate the negative effects of low irrigation on greenhouse sweet Cayenne pepper

AbstractSweet Cayenne pepper is a nutrient‐dense, sweet‐tasting greenhouse vegetable that often faces water stress in dry areas, and optimizing growth with minimum water consumption is crucial. In this study, we investigated the impacts of amino acids (AAs) foliar application on reducing water stress losses in sweet Cayenne pepper cv. “Lombard” under greenhouse conditions. The pepper bushes were irrigated in 3‐day and 6‐day intervals and simultaneously sprayed with an AA fertilizer (0, 150, and 300 mg/L). Vegetative growth, reproductive traits, and yield parameters were measured. Results showed significant decreases in the plant height, the roots length, SPAD, leaf greenness index, and the pepper leaves turn yellow under brief drought stress. The number of flowers was reduced by up to 50%, and the 3‐month yield decreased significantly from 7 to 5.05 kg/m2. However, with AAs foliar application, vegetative growth, fruit number, and yield increased significantly. The highest yield, 2.93 kg/plant, was observed in 300 mg/L AAs, while the minimum yield, with an average of 1.83 kg/plant recorded under water stress treatment without AAs application. The spray of AAs fertilizer remarkably improves the yield and quality of pepper fruit and reverses the destructive effects of low irrigation. The future direction could focus on the mechanism of the positive impact of AA foliar application on growth, yield, and quality of the fruit, particularly in water stress conditions, to further optimize growth and minimize water consumption.

Amino acids and amino sugars as indicators of the source and degradation state of sedimentary organic matter

Amino acids (AAs) and amino sugars (ASs), compounds ubiquitous to living organisms, can provide information regarding degradation states and bacterial contributions to sedimentary organic matter (SOM). However, very few studies have utilized the combination of AAs and ASs as a proxy to assess the influence of bacterial degradation on SOM in the Yellow Sea (YS). In this study, surface sediments from the YS were analyzed for AAs, ASs, total organic carbon (TOC), total nitrogen (TN), stable carbon isotope (δ13C), and grain size. The concentrations of AAs and ASs ranged from 3.29 to 26.65 μmol g−1 and from 0.50 to 9.11 μmol g−1, respectively, and together contributed 13.1% to TOC and 27.5% to TN. The concentrations of AAs and ASs were both positively correlated with the relative abundance of clay (<4 μm) (R2 = 0.73 and 0.79, respectively, p < 0.01), suggesting that hydrodynamic sorting influenced the distribution of SOM in the study area. Comparisons of the degradation indices (TOC normalized yields of AAs and ratio of AAs to ASs) indicated that the SOM in the South Yellow Sea (SYS) was more degraded than that in the North Yellow Sea (NYS). Variations in the glycine/serine and glucosamine/galactosamine ratios reflected a transition from fresh phytoplankton sourced organic matter (OM) to bacterial OM. Based on the yields of muramic acid (Mur), the bacterial OM contributed 17 ± 13% and 26 ± 19% to TOC and TN, respectively. High ratios of glucosamine to Mur (GlcN/Mur) indicated that the fraction of bacterial debris in the SYS was larger than that in the NYS. This study demonstrated the importance of bacteria in regulating the source and fate of SOM in the YS.

The influence of amino acids structure on their anaerobic digestion and the strategy to enhance biotransformation of refractory ones

Protein is an important component of organic waste, and it is first hydrolyzed to amino acids (AAs) during anaerobic digestion (AD). Until now, however, the effect of AAs structure on their AD has never been documented. In this paper the influence of AAs structure on their two-phase AD and the strategy to enhance biotransformation of refractory ones were investigated. Firstly, the AD performance of nineteen water-soluble AAs was compared. The methane yield of polar AAs was higher than that of non-polar ones (162.3–308.1 verse 10.7–140.5 mL/gCODadd) except glycine (284.1 mL/gCODadd). Further studies showed that the order of methane production with polar AAs, according to their carbon number, was 4-C < 6-C < 3-C < 5-C, while that with non-polar AAs was long-chain AAs (5 to 11-C) < short-chain AAs (2 to 3-C). The methane yield of non-polar ones with long-chain, according to their functional groups, was followed: proline > Alkyl AAs > Ph AAs. The mechanism investigation revealed the relationship between the structure of AAs and the amount of VFAs excluding propionate was consistent with the influence of AAs structure on methane yield. The microbes in AD system of refractory AAs had higher cell surface hydrophobicity (CSH) and lower cell membrane permeability (CMP), which led to lower enzyme activities and amino acid degradation as well as VFAs generation, and thus less methane production. Finally, the strategy to increase the biotransformation of refractory AAs was studied, and the methane yield was increased up to 139.8% by the application of rhamnolipid to change CSH and CMP in the digestion system. These findings elucidated the relationship between AAs structure and AD performance and provided new ideas to improve the biotransformation of refractory AAs.

44 Amino acids in livestock: A historical perspective

Abstract The advent of commercially viable synthetic amino acids (AA) and least cost formulation (LCF) have fundamentally changed swine and poultry diets over the past 40 years. Amino acids can be produced by chemical synthesis, hydrolysis of intact proteins and fermentation. Chemical synthesis of AA was first reported by Strecker (1850). Discovery of glutamate as the basis of Umami taste category (1907) spurred commercial AA production by hydrolysis. The discovery of commercially viable fermentative production of glutamate, by Kyowa Hakko Kogyo Co. (1957), revolutionized AA production. Their parallel discovery of lysine (Lys) production, using a natural C. glutmanicum mutant subsequently followed. This led to further screening for bacterial mutants for threonine (Thr, 1961), tryptophan (Trp, 1972), valine (Val, 1959) and isoleucine (Ile, 1972). The next milestone occurred with development of the first main-frame LCF programs (1960s). The first commercial application of dietary AA involved methionine (Met) for poultry, followed closely by Lys in swine. Use of other synthetic AA was cost-prohibitive, but they served as research tools. The next revolution involved recombinant DNA technology (1980s), which dramatically increased AA yield and reduced production cost. Simultaneously, development of PC based LCF enabled cost effective formulation. Subsequently, growth-derived AA ratio’s emerged from the labs of Fuller (1989) and Baker (1992). Patent expirations in the late 1980s led to new companies that produced rapid advances in fermentation methods, with new recombinant strains. Production cost declined further for Lys (1988), and production efficiencies allowed Thr (1995) and Trp (2000) to enter commercial diets. Advances in fermentation technology have enabled production of all ten essential AA. Extensive AA displacement of protein supplements has led to an ever-expanding global tonnage of AA for food and pet animals. With routine addition of 4–6 AA in swine diets, we question whether non-essential AA nitrogen may emerge as limiting (essential).

Application of Food-Grade Proteolytic Enzyme for the Hydrolysis of Regenerated Silk Fibroin fromBombyx mori

In vitrobiodegradation ofBombyx morisilk fibroin (SF) was studied using food-grade proteolytic enzymes to replace acid hydrolysis. Based on the residual protein quantity and yield of amino acids (AAs) after enzymatic hydrolysis, we evaluated the proteolytic enzyme process of SF. FoodPro and Alcalase that are classified as alkaline proteases are selected as two of the best candidate enzymes for hydrolysis of SF. The activity of these enzymes exhibits a broad range of pH (6.5 to 9.0) and temperature (50°C to 65°C). The single enzyme treatment of SF using FoodPro exhibited a hydrolytic efficiency of 20–25%, and &gt;2 g/L AAs were released after reaction for 3 h. A 2-stage enzymatic treatment using a combination of FoodPro and Flavourzyme in a sequence for a reaction time of 6 h was developed to enhance the efficiency of the proteolytic process. The yield of AAs and residual protein quantity in the enzymatic hydrolysates obtained from FoodPro-treated regenerated SF in the 1st step was 2,040 ± 23.7 mg/L and 70.6%, respectively. The yield of AAs was &gt; two-fold (4,519 ± 42.1 mg/L), whereas the residual protein quantity decreased to 55.1% after the Flavourzyme treatment (2nd step) compared to those of the single FoodPro treatment. In the mixed treatment by simultaneously using FoodPro and Flavourzyme, approximately 45% of SF was degraded and 4.5 g/L of AAs were released within 3 h of reaction time. The regenerated SF and its enzymatic hydrolysates were characterized by performing UV-visible spectra, gel electrophoresis, and size-exclusion chromatography analyses. In the 2-stage treatment using FoodPro initially and subsequently Flavourzyme, the aggregates and high molecular weight proteins of SF were dissociated and degraded into the low molecular weight proteins/peptides (10–15 kDa and 27 kDa). SF hydrolysates as functional food might be enzymatically produced using the commercial food-grade proteolytic enzymes.

Effects of Regulated Deficit Irrigation on Grain Yield and Quality Traits in Winter Wheat

A better understanding of the ini¬‚uence of water deficit on grain yield and quality in wheat is important for agronomists and farmers developing management practices for improved quality. A barrel experiment was conducted in 2011-2012 and 2012-2013 to investigate the effects of water deficit on the relationship between grain yield and quality of winter wheat. The experimental treatments of three growth stages (beginning of spring growth, stem elongation, and grain filling) x three levels of water deficit (60% to 65%, 50% to 55%, and 40% to 45% of field capacity (FC) for light, moderate, and severe deficit, respectively) were laid out in a randomized complete block design with three replicates. A non-deficit control (CK) (75% to 85% FC from sowing to maturity) with three replications was also included. A negative linear correlation between grain protein content (GPC) and soil water content (SWC) was observed at the stem elongation stage in both years. Light or moderate water deficit prior to the stem elongation stage did not significantly reduce grain yield (GY), protein yield (PY), or amino acid yield (AAY) compared with full irrigation. Light water deficit during the grain filling stage did not significantly decrease grain yield and was significantly associated with improved grain quality and water conservation. The results demonstrated that the relationship between GY and GPC changed due to different treatments. Findings suggested that light or moderate water deficit prior to the stem elongation stage, or light water deficit at the grain filling stage, promote high yield and grain quality in winter wheat.

The roles of microorganisms in litter decomposition and soil formation

Much has been learned about the microbial decomposition of plant litter, but relatively little is known about microbial contributions to litter and soil chemistry. We conducted a 3-year litterbag experiment and measured hydrolyzable amino acids (AA) and amino sugars (AS) to gain insights about microbial contributions to the chemical characteristics of decomposing litter and soil. Microscopic observations of hyphae were used to estimate fungal contributions to litter. The carbon (C)-normalized yields of AA and AS increased during decomposition along with nitrogen (N), indicating a shift in chemical characteristics from C-rich plant-derived biopolymers to N-rich, microbially-derived biochemicals. The contributions of fungal biomass to C and N were minor, but necromass of fungi as melanized and clamp-bearing hyphae increased during litter decomposition. Yields of glucosamine and galactosamine in litter approached those in microorganisms, particularly bacteria, suggesting major contributions of bacterial residues to litter during decomposition. The microbial contributions to decomposing litter were consistent with those observed in organic and mineral soils. Microorganisms play important roles in the organization and stabilization of soil organic matter as well as N immobilization and organic C preservation.

Vascular Sources of Amino Acids for Milk Protein Synthesis in Goats at Two Stages of Lactation

An arteriovenous technique, combined with a 30-h i.v. infusion of [5-13CH3]Met and [5,5,5-2H]Leu, was used to monitor mammary uptake of free amino acid (AA) and to estimate the proportion of casein synthesized from circulating peptides in goats in early and late lactation. At both stages, kinetics was performed on the last day of consecutive 5.5-d periods. The first period was an i.v. infusion of saline and the second an i.v. infusion of lysine (8.9 g/h) plus methionine (2 g/h). Net uptake of essential AA and protein yields were higher in early than in late lactation. Uptake of free Met, His, and Pro was less than, uptake of Tyr and Lys was equal to, and uptake of Arg, Leu, Val, and Ile was greater than milk protein synthesis. Peptide uptake, estimated from the difference in casein and plasma free AA enrichment, accounted for a larger fraction of casein-Met (17 vs. 8%) and casein-Leu (27 vs. 12%) in late than in early lactation. Small decreases in mammary blood flow, AA transport activity, and AA concentrations accounted for the lower uptake of AA in late compared with early lactation. Based on our studies of several AA, the utilization of circulating peptides for casein synthesis appears to be a general phenomenon.

Concentrations and Ruminal Degradabilities of Amino Acids from Wheat and Triticale Forage and Grain

AbstractA study was conducted to provide comparative data on amino acid (AA) concentrations in forage and grain of wheat (Triticum aestivum L.) and triticale (✕Triticosecale Wittmack), before and after ruminal degradation, while assessing forage and grain yield potential. Forage samples of Terral ‘817’ wheat, ‘Jenkins’ triticale, and ‘Morrison’ triticale were harvested at growth stages 5.0, 6.5, and 8.0 and AA concentrations and yield determined. Wheat and triticale forage samples were incubated in Dacron bags for 24 h in the rumen of cows to determine the comparative ruminal degradability of their EAA. Forage production among the three cultivars in 1987‐1988 was similar, but in 1988‐1989, Jenkins produced 15% more forage than Terral 817, which produced 14% more forage than Morrison. Essential amino acid concentrations in Jenkins triticale forage were equal to or greater than Terral 817 wheat or Morrison triticale; however, Morrison grain had a greater concentration of all EAA, except lysine, than did grain of Terral 817 or Jenkins. The EAA in Terral 817 forage averaged 25% higher in potential degradability in the rumen than EAA in Jenkins. Terral 817 and Morrison maintained a higher grain yield response to forage removal in contrast to Jenkins. Differences in forage yield, grain yield, and EAA concentration could not always be separated by species. The data suggest that triticale may produce forage and grain yields equal or greater than that of winter wheat while providing a better source of ruminally undegradable EAA.