It's usually a growth medium containing elemental sulfur or thiosulphate as sole energy source as well as a pH indicator. You can measure sulfate as well to make sure you don't have organic contaminants lowering the pH, the only way I've personally done this is digestion with nitric acid followed by precipitation with barium chloride, filtration with a non-ash producing filter paper and calcination in an oven, but that's analytical chemistry so you may have to have it done by another lab.

The article has most of methodology.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4950637/

Dear Abinubli Tariswafi Mawarid '

Please see the following link:-

https://academic.oup.com/femsec/article/88/3/538/586123

Best and kind regard

follow these links to answer your question

https://scholar.google.com/scholar?q=kit+for+analysing+sulphur+oxidation+of+bacteria&hl=ar&as_sdt=0&as_vis=1&oi=scholart&sa=X&ved=0ahUKEwje0NzD3KXaAhXlB5oKHT5NB30QgQMIJDAA

Article Links between sulphur oxidation and sulphur oxidizing bacter...

http://www.microbialanalysis.com/en/q-bioanalyses/sulfur/sulfur-oxidizing-bacteria