Microbiological Removal of Hydrogen Sulphide from Natural Rubber Latex Processing Wastewater by Acidithiobacillus thiooxidans strain UniMAP-AIN01

Abstract

Acidithiobacillus thiooxidans is an acidophilic chemoautotrophic bacterium which capable to convert the toxic hydrogen sulphide in wastewater into non-toxic compounds. The Acidithiobacillus thiooxidans strain UniMAP-AIN01 was previously isolated from a local natural rubber latex processing mill. In this study, the A. thiooxidans strain UniMAP-AIN01 was subjected to its growth performance evaluation in the wastewater of natural rubber latex. The sulphur content in the wastewater was utilized as energy source and support their growth. It was discovered that the A. thiooxidans strain UniMAP-AIN01 has long doubling time of 2 days in thiosulphate medium, while log phase lasted until 6^th day of incubation. Regression analysis of the growth kinetic was established with the aid of POLYMATH software. The precision value obtained as follows; linear regression, R² of 0.9811, adjusted linear regression, Adj R² of 0.9764, root mean square deviation, RMSD of 0.0015, and variance of 1.992 × 10⁻⁵ indicate the data is highly correlated and error is insignificant. Assessment on hydrogen sulphide removal efficiency using locally isolated A. thiooxidans strain UniMAP-AIN01 revealed 90% of hydrogen sulphide removal was achieved within a week.