Insight into Arthrospira platensis Δ9 desaturase: a key enzyme in poly-unsaturated fatty acid synthesis

Improved muscle fatty acid composition and oxidative stability in lambs grazing on sainfoin pasture

As a mode of animal management, grazing on pasture has the potential to improve animal performance and provide healthy meat. However, there is little information about the effects of lamb meat quality grazed on sainfoin pasture. Therefore, the present study was conducted to compare the fatty acid composition and oxidative stability of growing lambs. The twenty-four lambs were randomly divided into grazing on sainfoin pasture (GS) or feeding indoors pelleted total mixed ration (FI). The results show that GS had the higher polyunsaturated fatty acids (PUFA), especially n-3 PUFA (P = 0.002), and beneficial for nutritional index of fatty acid. Corresponding that GS had lower the Thiobarbituric acid reactive substance (TBARS) in raw (P = 0.005) and cooked meat (P = 0.008). The GS had higher total phenols (P = 0.021), ferric reducing antioxidant power (FRAP) (P = 0.048) and α-Tocopherol of meat (P = 0.004). In conclusion, grazing on sainfoin pasture in lambs can improve muscle fatty acid composition and oxidative stability than feeding indoors.

Key Enzymes in Fatty Acid Synthesis Pathway for Bioactive Lipids Biosynthesis

Dietary bioactive lipids, one of the three primary nutrients, is not only essential for growth and provides nutrients and energy for life's activities but can also help to guard against disease, such as Alzheimer's and cardiovascular diseases, which further strengthen the immune system and maintain many body functions. Many microorganisms, such as yeast, algae, and marine fungi, have been widely developed for dietary bioactive lipids production. These biosynthetic processes were not limited by the climate and ground, which are also responsible for superiority of shorter periods and high conversion rate. However, the production process was also exposed to the challenges of low stability, concentration, and productivity, which was derived from the limited knowledge about the critical enzyme in the metabolic pathway. Fortunately, the development of enzymatic research methods provides powerful tools to understand the catalytic process, including site-specific mutagenesis, protein dynamic simulation, and metabolic engineering technology. Thus, we review the characteristics of critical desaturase and elongase involved in the fatty acids' synthesis metabolic pathway, which aims to not only provide extensive data for enzyme rational design and modification but also provides a more profound and comprehensive understanding of the dietary bioactive lipids' synthetic process.

Extracellular neutral protease from Arthrospira platensis: Production, optimization and partial characterization

Proteases are industrially important catalysts. They belong to a complex family of enzymes that perform highly focused proteolysis functions. Given their potential use, there has been renewed interest in the discovery of proteases with novel properties and a constant thrust to optimize the enzyme production. In the present study, a novel extracellular neutral protease produced from Arthrospira platensis was detected and characterized. Its proteolytic activity was strongly activated by β-mercaptoethanol, 5,5-dithio-bis-(2-nitrobenzoic acid) and highly inhibited by Hg²⁺ and Zn²⁺ metal ions which support the fact that the studied protease belongs to the cysteine protease family. Using statistical modelling methodology, the logistic model has been selected to predict A. platensis growth-kinetic values. The optimal culture conditions for neutral protease production were found using Box-Behnken Design. The maximum experimental protease activities (159.79 U/mL) was achieved after 13 days of culture in an optimized Zarrouk medium containing 0.625 g/L NaCl, 0.625 g/L K₂HPO₄ and set on 9.5 initial pH. The extracellular protease of A. platensis can easily be used in the food industry for its important activity at neutral pH and its low production cost since it is a valuation of the residual culture medium after biomass recovery.

Delta or Omega? Δ12 (ω6) fatty acid desaturases count 3C after the pre-existing double bond

Fatty acid desaturases (FADs) represent a class of oxygen-dependent enzymes that dehydrogenate C-C bonds in the fatty acids (FAs) producing unsaturated CC double bonds that markedly change the properties of biological membranes. FADs are highly specific towards their acyl substrates, the position and configuration of the introduced double bonds. The double bond positioning of soluble acyl-carrier-protein Δ9-FADs was determined relative to the carboxyl end of a FA. Similar mode was suggested for the acyl-lipid Δ12-FADs (also known as ω6-FADs), however, their exact counting order remain unknown. Here we used monounsaturated odd- (17:1Δ¹⁰) and even-chain (18:1Δ¹¹) FAs to show that acyl-lipid Δ12-FADs of, at least, two cyanobacterial species, Gloeobacter violaceus and Synechocystis sp. strain PCC 6803, use neither end of the fatty acid (Δ or ω) as a counting reference point; but count three carbons toward the methyl end from an existing double bond in the monoene precursors irrespective of a FA chain length.

Nutritional evaluation and human health-promoting potential of compounds biosynthesized by native microalgae from the Peruvian Amazon

A plausible strategy to mitigate socioeconomic problems in the Peruvian Amazon is through the sustainable exploitation of biodiversity resources, such as native microalgae. Several studies worldwide affirm that these microorganisms are excellent sources of higher value products for human nutrition and possess health-promoting biochemicals, but these attributes are unknown for the native microalgae of Peru. Therefore, the aim of this investigation was to evaluate the nutritional and human health-promoting potential of compounds biosynthesized by native microalgae from the Peruvian Amazon. Ten native microalgae strains of the groups cyanobacteria and chlorophyta were cultured in BG-11 medium and their biomass harvested and dried. Standardized methods were then used to determine proximate composition, fatty acids and amino acids composition, antioxidant activity, and total phenolic content. All ten microalgae strains produce primary nutrients, the entire spectrum of essential amino acids, essential fatty acids, and 3 of the 10 microalgae strains produced eisosapentaenoic acid. Additionally, all microalgae strains exhibited antioxidant activities and contained phenolic compounds. In conclusion, native microalgae strains from the Peruvian Amazon analyzed in this study possess the ability to biosynthesize and accumulate several nutrients and compounds with human health-promoting potential.

Carotenoids Overproduction in Dunaliella Sp.: Transcriptional Changes and New Insights through Lycopene β Cyclase Regulation

Dunaliella is a green microalga known for its ability to produce high levels of carotenoids under well-defined growing conditions. Molecular responses to the simultaneous effect of increasing salinity, light intensity and decrease of nitrogen availability were investigated in terms of their effect on different metabolic pathways (isoprenoids synthesis, glycolysis, carbohydrate use, etc.) by following the transcriptional regulation of enolase (ENO), 1-deoxy-D-xylulose 5-phosphate synthase (DXS), lycopene β-cyclase (LCYB), carotene globule protein (CGP), chloroplast-localized heat shock protein (HSP70), and chloroplast ribulose phosphate-3-epimerase (RPE) genes. The intracellular production of carotenoid was increased five times in stressed Dunaliella cells compared to those grown in an unstressed condition. At transcriptional levels, ENO implicated in glycolysis, and revealing about polysaccharides degradation, showed a two-stage response during the first 72 h. Genes directly involved in β-carotene accumulation, namely, CGP and LCYB, revealed the most important increase by about 54 and 10 folds, respectively. In silico sequence analysis, along with 3D modeling studies, were performed to identify possible posttranslational modifications of CGP and LCYB proteins. Our results described, for the first time, their probable regulation by sumoylation covalent attachment as well as the presence of expressed SUMO (small ubiquitin-related modifier) protein in Dunaliella sp.