Isolation, identification and in silico analysis of alpha-amylase gene of Aspergillus niger strain CSA35 obtained from cassava undergoing spoilage

Biochemical Characterization of Solid-State Fermented Cassava Stem (Manihot esculenta Crantz-MEC) and Its Application in Poultry Feed Formulation

The utilization of solid-state fermentation (SSF) of cassava stem, "Manihot esculenta Crantz-MEC", is central in this study for its biochemical characterization and formulation of a new poultry feed using a starter culture of Rhizopus oligosporus strain at specified experimental conditions (26 ± 1 °C, 72 h and pH 6). The coupling of R. oligosporus strain to SSF of cassava stem caused significant increase (p < 0.05) in glucose, total reducing sugar (TRS) and total soluble protein (TSP) concentrations at variable but marked effect at 10% inoculum size of the fermented cassava stem, as compared with the unfermented type. Further evaluations of DPPH-radical scavenging activity, total phenolic and flavonoid contents (TPC and TFC), as indices of correlation to antioxidant activity in both fermented and unfermented cassava stems showed marked significant difference with prominence at 10% inoculum size (p < 0.05). Results of high α-amylase activities were observed in fermented cassava stem when compared with the unfermented type (p < 0.05) at increasing inoculum sizes (5-15%) but with marked dominance at 10%. Broiler chicks fed with formulated feed showed marked increase in weight gain at 10% inoculum size of the fermented cassava stem relative to a typical poultry feed. Also, examination of alkaline phosphatase (ALP) and alanine and aspartate aminotransferases (ALT and AST) showed no marked difference in their activities for fermented feed at increasing inoculum sizes when compared with typical poultry feed, respectively (p > 0.05). The study hereby suggests the use of fermented cassava stem as an alternative raw material during formulation of livestock feeds.

A review of limitations to using cassava meal in poultry diets and the potential role of exogenous microbial enzymes

Cassava (Manihot esculenta), a crop grown in the tropics, is increasingly becoming a vital feed resource for human beings and livestock. Traditionally, cassava has been used primarily as a source of food for humans. However, it is becoming an increasingly important ingredient in livestock feed. The use of cassava leaves and roots in poultry diets is limited because of nutrient imbalances and toxins (hydrogen cyanide (HCN)) found in them. High HCN is reduced to innocuous levels by processing the ingredient using a simple sun drying method. Plant fibre content can be reduced and made available for use by poultry through the use of exogenous enzymes. More recent innovative interventions in biotechnology have brought about various exogenous enzymes that can help improve the digestibility of fibrous diets. These include, among others, carbohydrases, proteases and phytases. The extent to which the animals utilise nutrients is influenced by the type of enzyme and the physicochemical properties of the feed ingredient. This review aims to collate information on the current state of knowledge on the use of exogenous microbial enzymes in diets containing cassava and how the enzymes that target carbohydrates might be useful in making nutrient available for poultry.

Molecular strategies to enhance stability and catalysis of extremophile-derived α-amylase using computational biology

α-Amylase is the most significant glycoside hydrolase having applications in various industries. It cleaves the α,1-4 glucosidic linkages of polysaccharides like starch, glycogen to yield a small polymer of glucose in α-anomeric configuration. α-Amylase is produced by all the three domains of life but microorganisms are preferred sources for industrial-scale production due to several advantages. Enormous studies and research have been done in this field in the past few decades. Still, it is requisite to work on enzyme stability and catalysis, as it loses its functionality in extreme. As the enzyme loses its structural and catalytic property under extreme environmental conditions, it is mandatory to confer some potential strategies for enhancing enzyme behaviour in such conditions. This limitation of an enzyme can be overcome up to some extent by extremophiles. They serve as an excellent source of α-amylase with outstanding features. This review is an attempt to encapsulate some structure-based strategies for improving enzyme behaviour thereby enabling researchers to selectively amend any of the strategies as per requirement during upstream and downstream processing for higher enzyme yield and stability. Thus, it will provide some cutting-edge strategies for tailoring α-amylase producing organism and enzyme with the help of several computational biology tools.

Exploring the binding interactions of structurally diverse dichalcogenoimidodiphosphinate ligands with α-amylase: Spectroscopic approach coupled with molecular docking

Postprandial hyperglycemia has orchestrated untimely death among diabetic patients over the decades and regulation of α-amylase activity is now becoming a promising management option for type 2 diabetes. The present study investigated the binding interactions of three structurally diverse dichalcogenoimidodiphosphinate ligands with α-amylase to ascertain the affinity of the ligands for α-amylase using spectroscopic and molecular docking methods. The ligands were characterized using ¹H and ³¹P NMR spectroscopy and CHN analysis. Diselenoimidodiphosphinate ligand (DY300), dithioimidodiphosphinate ligand (DY301), and thioselenoimidodiphosphinate ligand (DY302) quenched the intrinsic fluorescence intensity of α-amylase via a static quenching mechanism with bimolecular quenching constant (Kq) values in the order of x10¹¹ M^-1s^-1, indicating formation of enzyme-ligand complexes. A binding stoichiometry of n≈1 was observed for α-amylase, with high binding constants (Ka). α-Amylase inhibition was as follow: Acarbose > DY301>DY300>DY302. Values of thermodynamic parameters obtained at temperatures investigated (298, 304 and 310 K) revealed spontaneous complex formation (ΔG<0) between the ligands and α-amylase; the main driving forces were hydrophobic interactions (with DY300, DY301, except DY302). UV–visible spectroscopy and Förster resonance energy transfer (FRET) affirmed change in enzyme conformation and binding occurrence. Molecular docking revealed ligands interaction with α-amylase via some key catalytic site amino acid residues (Asp197, Glu233 and Asp300). DY301 perhaps showed highest α-amylase inhibition (IC₅₀, 268.11 ± 0.74 μM) due to its moderately high affinity and composition of two sulphide bonds unlike the others. This study might provide theoretical basis for development of novel α-amylase inhibitors from dichalcogenoimidodiphosphinate ligands for management of postprandial hyperglycemia.

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Interaction of α-amylase with dichalcogenoimidodiphosphinate ligands was studied.

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Spectroscopy and molecular docking explored the interaction mechanisms.

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The main driving forces were hydrophobic interactions with DY300 and DY301.

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The ligands quenched α-amylase fluorescence intensity by static mechanism.

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Dichalcogenoimidodiphosphinate ligands inhibited α-amylase activity.

Secretomic analysis of cheap enzymatic cocktails of Aspergillus niger LBM 134 grown on cassava bagasse and sugarcane bagasse

Currently, agroindustrial wastes are little used for generating value-added products; hence, their use of these waste to produce enzymatic cocktails for the conversion of lignocellulosic biomass to fermentable sugars is a very interesting alternative in the second-generation bioethanol process. The Ascomycota fungus Aspergillus niger LBM 134 produces hydrolytic enzymes in large proportions. In this work, A. niger LBM 134 was grown on sugarcane and cassava bagasses under optimized conditions. To identify the extracellular enzymes involved in the degradation of these agroindustrial wastes, the secretomes of the culture supernatants of the fungus were analyzed and validated by biochemical assays of the enzymatic activities. A. niger LBM 134 secreted higher quantities of xylanases and accessory hemicellulases when it grew on sugarcane bagasse, whereas more cellulases, amylases, and pectinases were secreted when it grew on cassava bagasse. These findings suggest two promising enzyme cocktails for the hydrolysis of lignocellulose carbohydrate polymers to fermentable sugars. These bioinformatic analysis were functional validates through enzymatic biochemical assays that confirm the biotechnological potential of A. niger LBM 134 for the bioconversion of hemicellulosic substrates such as sugarcane and cassava bagasses.

Microbial Alpha-Amylase Production: Progress, Challenges and Perspectives

Alpha-amylase reputes for starch modification by breaking of 1-4 glycosidic bands and is widely applied in different industrial sectors. Microorganisms express unique alpha-amylases with thermostable and halotolerant characteristics dependent on the microorganism’s intrinsic features. Likewise, genetic engineering methods are applied to produce enzymes with higher stability in contrast to wild types. As there are widespread application of α-amylase in industry, optimization methods like RSM are used to improve the production of the enzyme ex vivo. This study aimed to review the latest researches on the production improvement and stability of α-amylase.

The Dual Prey-Inactivation Strategy of Spiders-In-Depth Venomic Analysis of Cupiennius salei

Most knowledge of spider venom concerns neurotoxins acting on ion channels, whereas proteins and their significance for the envenomation process are neglected. The here presented comprehensive analysis of the venom gland transcriptome and proteome of Cupiennius salei focusses on proteins and cysteine-containing peptides and offers new insight into the structure and function of spider venom, here described as the dual prey-inactivation strategy. After venom injection, many enzymes and proteins, dominated by α-amylase, angiotensin-converting enzyme, and cysteine-rich secretory proteins, interact with main metabolic pathways, leading to a major disturbance of the cellular homeostasis. Hyaluronidase and cytolytic peptides destroy tissue and membranes, thus supporting the spread of other venom compounds. We detected 81 transcripts of neurotoxins from 13 peptide families, whereof two families comprise 93.7% of all cysteine-containing peptides. This raises the question of the importance of the other low-expressed peptide families. The identification of a venom gland-specific defensin-like peptide and an aga-toxin-like peptide in the hemocytes offers an important clue on the recruitment and neofunctionalization of body proteins and peptides as the origin of toxins.