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Title: A natural source of anthraquinone dye intermediates : production and identification of microbial anthraquinones, an environmentally friendly method of producing dye intermediates, and their conversion to textile dyestuffs
Author: Hobson, Debra Kay
ISNI:       0000 0004 2729 6278
Awarding Body: University of Bradford
Current Institution: University of Bradford
Date of Award: 1995
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An environmentally friendly route to anthraquinone dyes has been developed by exploiting the anthraquinone biochromophores produced by microorganisms. An extensive screen of biochromophore producers, including species of Pyrenophora, Trichoderma, Drechslera, Phoma and Curvularia, was undertaken. The biochromophores were extracted from the mycelia with acetone and characterised by means of TLC, HPLC, GLC, mass spectrometry and UV /vis spectrophotometry. Most of the organisms produced anthraquinones unsuitable for conversion to anthraquinone dyes/dye intermediates. Problems included the anthraquinones being produced only at low temperatures, being too complex for dye conversion, possessing substitutions in the P-position, or being produced association with fatty material or as mixtures and thus not of high enough purity for dye conversion. Two strains of Curvularia, C. lunata and C. ramosa produced cynodontin (1,4,5,8- tetrahydroxy-3-methylanthraquinone) of the required purity although initial yields were poor and associated with melanin. Strain selection and manipulation of the culture medium resulted in elimination of melanin and cynodontin yields of up to l.0g dm-3. The culture medium developed contains nitrate as the nitrogen source and 6% sucrose as the carbohydrate source. Zinc was shown to influence the balance between anthraquinone and melanin production whilst a cycle of l2h white light/l2h respite from light produced a lO fold increase in cynodontin yield. The optimum pH was pH 7.0 whilst a temperature of 28°C and aeration of around 4 dm3 minot with impeller speed of 400rpm was preferred. Cynodontin, once acceptable as a dyestuff in its own right, no longer has the washfastness required for modern detergents. However, as an intermediate, cynodontin requires only a few simple chemical steps to produce a blue biodye which is an analogue of Disperse Blue 7 and a green biodye which is an analogue of Acid Green 28. Both biodyes appear brighter than their chemically synthesised analogue and also possess slightly better fastness properties than the conventional dyes when applied to knitted polyamide.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available