Study On The Biological Properties Of A Pigment-Producing Strain And The Isolation And Identification Of The Pigment

Pigments are used in a wide range of applications,and the use of microorganisms as cellular factories for pigment production is a trend in this industry,and more and more scholars are working on related research.In this paper,we isolated and identified a strain that can secrete pigments in large quantities,determined the species relationship,optimized the culture medium and its liquid fermentation process,and isolated and purified the pigments in the metabolites by combining separation techniques and wave spectrometry.1.Classical morphological features and molecular biological analyses were used to determine the species relationship of a pigment producing strain incidentally discovered in this experiment.Morphologically,a large number of dark green spores were attached to the surface of the colony,with dense white hyphae at the edge.The hyphae had transverse septa,and the conidiophore had multiple branches,and the shape was broom-like.From the molecular point of view,the strain shared 100% homology with Talaromyces atroroseus by ITS sequence alignment.After construction of phylogenetic tree,the strain was identified as Talaromyces atroroseus and named Talaromyces atroroseus LWT-1.2.The optimum medium was screened by single-factor experiment and orthogonal test with the criteria of mycelial biomass and pigment yield,respectively.The results showed that the best medium formula to affect the mycelial biomass of the strain was(g/L)dextrin 50.0,peptone 15.0,magnesium sulfate 0.4,glycerol 45.0;the best medium formula to affect the color value of the pigment produced by the strain was(g/L)dextrin30.0,peptone10.0,magnesium sulfate 0.3,glycerol 40.0.3.The optimum fermentation conditions for the liquid culture of Talaromyces atroroseus LWT-1,including temperature,rotational speed,loading volume and incubation time,were determined by single-factor and orthogonal tests,using mycelial biomass and pigment yield as criteria,respectively.The results showed that the optimal fermentation process for affecting the mycelium biomass of the strain was 24℃,170r/min,60 m L of liquid,and 96 h of incubation time.The optimal fermentation process for the color value of the pigment produced by the strain was 32℃,170 r/min,60 m L of liquid,and 120 h of incubation time.4.Repeated extraction of the fermentation broth obtained from large-scale fermentation using ethyl acetate to obtain crude pigment extracts.The crude pigment extract was separated and purified by Vacuum Liquid Chromatography separation,Reversed-phase Silica Columns separation,Preparative Thin Layer Chromatography,Gel Column separation,Normal Phase Silica Gel Column separation,Thin Layer Chromatography and Nuclear Magnetic Resonance analysis.The results showed that one pigment was isolated and purified,accounting for 2.9% of the total yield,and it was identified as compound talaroconvolutin A by spectroscopy.