The objective of this research was to study the antibacterial activity of 16 samples of indigo dyed fabrics that are produced and sold in Sakon Nakhon Province. Effect of moisture and pH of indigo dyed fabrics on bacterial growth were also determined. The result of the study shows inhibition of S. aureus TISTR 746 and E. coli TISTR 073 by agar diffusion plate test all samples could inhibit Saureus TISTR 746 (accounted as 100%) and only 9 samples could inhibit E. coli TISTR 073 (accounted as 56.25%). Whereas the study of antibacterial activity by AATCC test method 100-2004 at 24 hours was found that the natural indigo dyed fabrics code A3-1 could inhibit both bacterial strains in the highest level. The result also shows the effect of moisture and pH of indigo dyed fabrics on bacterial growth it was found that the increased humidity levels of indigo dyed fabrics have effect on the reduction of the inhibition efficacy of both strains. While indigo dyed fabric with pH 3.0 was found to inhibit most of the growth of both strains. In addition images obtained using a scanning electron microscope (SEM) could clearly confirm the property of indigo dyed fabric on inhibition of S. Aureus TISTR 746 and E. coli TISTR 073.

This research investigated the effect of antibacterial activity of Guava leaves extract. Antibacterial activity was determined by agar well diffusion method and test with Staphylococcus aureus Bacillus cereus and Escherichia coli. The results showed that Guava leaves crude extract best inhibited the growth of Bacillus cereus followed by Staphylococcus aureus and Escherichia coli with a mean inhibition zone was 22.0 ±0.3 19.00 ± 0.2 and 14.5 ± 0.3 mm respectively. When comparison antibacterial activity between Guava leaves extract with ampicillin 0.010 mg.

The objectives of this research were to characterize growth and melanin production on different culture media effect of copper ion and cobalt ion on growth and melanin production including antibacterial activity of crude melanin. The results revealed that actinomycetes strain PNST-01 have good growth on ISP-7 medium synthetic medium while strain PRBS-12 grow very well on ISP-3 medium complex medium. Both strains produced high amount of melanin showing brownish colony on ISP-7 medium but there is no melanin pigment production on ISP-1 medium and ISP-6 medium. Moreover the growth rate was reduced and both strains could not produce melanin pigment on ISP-7 medium without supplement with copper chloride and cobalt chloride. Crude melanin extract of strain PNST-01 showed antimicrobial activity against Bacillus cereus ATCC 11778 Bacillus subtilis ATCC 6633 and Staphylococcus aureus ATCC 25923 but could not inhibit Escherichia coli Shigella dysenteriae Salmonella typhi Klebsiella pneumoniae Serratia marcescens Pseudomonas aeruginosa and Streptococcus pyogenes . While crude melanin extract of strain PRBS-12 gave antimicrobial activity only on B. cereus ATCC 11778 and B. subtilis ATCC 6633. Based on the study the results can be used as key information for further development of melanin production and application in various industries.

In this study natural rubber latex/chitosan (NRL/CT) composites were prepared by latex mixing. The effects of chitosan on latex properties and physical Properties of NRL/CT composite films were focused. It was found that there was no significant change in the latex properties with increasing CT content. Increasing CT contents of 0.5 to 8.0 phr caused the rising of 300 % modulus of the NRL/CT composite whereas the opposite trend was found for tensile strength and elongation at break. The antimicrobial efficacy of the chitosan-incorporated rubber was slightly enhanced from that of the non-chitosan rubber. By comprehensive consideration CT content suitable for antibacterial gloves according to Thai industrial standards (TIS 1056-1: 2013) was 1 phr. For other latex products that require high modulus and antibacterial activity such as tubing pillow foam rubber nipple and catheter CT could be used at higher contents from 2 to 4 phr.