A study of natural dyes extracted from actinomycetes isolates on silk fabrics / Wan Mohd Fathil Wan Yusoff

Natural dyes extracted from microorganism offers many advantages such as exhibit better biodegradability, have higher compatibility with the environment, lower toxicity and allergic reaction to users. Thus, increases the interest among researcher to replace natural dyes with commonly used synthetic dyes. Synthetic dyes are known to have hazardous effects such as carcinogenicity, possibility of ambient pollution and potential allergies to the user. This thesis is an attempt to study the extraction of dyes from actinomycetes using Ultrasound Assisted Extraction (UAE), Boiling Water Extraction (BWE), Microwave Assisted Extraction (MAE) and Water Extraction (WE). Analyzing the strength and colourfastness of the dyes on silk fabrics and to identify selected actinomycetes based on morphology and 16S rRNA gene analysis. Good colour fastness of the dyed substrate to washing, perspiration, rubbing was observed for mordanted samples giving rating from 4 to 5. Good rating for light fastness was also recorded for mordanted samples in between rating 5 to 7. However, lower rating was recorded for unmordanted samples which gave rating lower than 3. The CIEL*a*b* showing L* values of mordanted dyed fabrics gave lower value compared with unmordanted, for instance G1A39 recorded lowest L* of 60.43. As for K/S and ΔE value, the results recorded showing mordanted gave higher values than unmordanted with G1A6 have the highest K/S value of 3.146 and G2A24 record the highest ΔE value of 36.28. This showing the mordant treatment increased the strength of dyes on the fabrics. Three samples namely G1A39, G1A45 and L4E3 were selected for species identification due to excellent results in term of their colourfastness and colour strength. The morphology study showed these samples have typical characteristic of Streptomyces such as spore formation, colony elevation, wrinkled colony and spore chain formation. Moreover, these samples were identified through the alignment of 16S rRNA gene using BLAST tool showing the species for G1A39, G1A45 and L4E3 are Streptomyces diastaticus; strain NBRC 15402, Streptomyces thermocarboxidus; strain NBRC 16323 and Streptomyces spp. CCM_MD2014, complete genome. As conclusion, UAE and MAE methods are seen as the most effective method for extracting dyes from actinomycetes based on color volume and color strengths. This method also offers lower cost production and can produce dyes in large quantities. Hence, these two methods have great potential to be exploited in the production of dyes from microorganism.