Duangporn Kantachote and Wasan Innuwat

pp. 649 - 657

Abstract

Thiobacillus spp. are extensively used worldwide for removal of both organic and inorganic sulphur
compounds in wastewater; however, a little used in Thailand. Southern Thailand has numerous rubber
factories producing wastewater containing high amounts of those compounds. Therefore, in this study, 4
Thiobacillus sp. were isolated from wastewaters of domestic and rubber factories. Each isolate grew both
aerobically and anaerobically as both a chemolithotroph and chemoorganotroph. All isolates grew in a pH
range from 2.0-7.0 with an optimum of 6.5 and in the temperature range of 25-45ºC with an optimum between
30-35ºC. After 14 days of incubation in rubber sheet wastewater Thiobacillus sp. WI 1 produced the highest
removal of COD at 54%; but removal of BOD was only 33%. In contrast, strain WI 4 produced the highest
BOD removal at 83% with removal of COD at only 46%.