Amylase production with purple yam as substrate

Description

This dataset contains the raw experimental data supporting the production of amylolytic enzymes by native microorganisms using purple yam (Dioscorea alata L.) flour as substrate. It includes amylolytic activity (U/mL) and total protein measurements from the screening of 24 native isolates, and enzymatic activity data from the three-way factorial design evaluating the effects of temperature, pH, and substrate concentration on amylase production by Streptomyces daghestanicus (S17H) and Aspergillus fumigatus (H2H). All measurements were performed in replicates and include uninoculated controls. Data are provided in spreadsheet format (.xlsx), with variables, units, and experimental conditions specified in each file.

Steps to reproduce

Native isolates were recovered from rhizosphere, compost, and purple yam tuber samples and maintained in the CEMBIO collection (Colegio Mayor de Antioquia). Streptomyces inocula were prepared from GYM agar colonies resuspended in peptone water with Tween 80 (0.1% v/v) to a McFarland #1 standard; fungal inocula were prepared from PDA colonies to 1×10⁶ conidia/mL. For the screening, each isolate was cultured in 100 mL Erlenmeyer flasks containing 20 mL of a mineral medium supplemented with 10 g/L purple yam flour, using an ammonium-based medium (pH 7.0) for Streptomyces and a nitrate-based medium (pH 6.0) for fungi. Cultures were incubated at 30 °C and 150 rpm for 7 days in triplicate. Cell-free supernatants were recovered by centrifugation (12,000 rpm, 4 °C). Amylolytic activity was determined by the 3,5-dinitrosalicylic acid (DNS) method (Miller, 1959), measuring reducing sugars released from 1% (w/v) soluble starch after incubation at 40 °C for 30 min, with absorbance read at 540 nm on a GENESYS 105 spectrophotometer; one unit (U) was defined as the amount of enzyme releasing 1 µmol of reducing sugar per minute. Total protein was quantified by the Lowry method (Lowry et al., 1951) using bovine serum albumin as standard, and specific activity was expressed as U/mg protein. For isolates S17H and H2H, the effects of temperature, pH, and purple yam flour concentration on amylase production were evaluated using a three-level, three-factor design (four replicates per treatment), with uninoculated controls under each condition. Data were analyzed by three-way ANOVA (p < 0.05). Statistical analyses were performed in Statgraphics Centurion XVII.

Institutions

• Institución Universitaria Colegio Mayor de Antioquia

  Antioquia, Medellín

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