Wikipedia says "In industry dimethyl sulfide is produced by treating hydrogen sulfide with excess methanol over an aluminium oxide catalyst”.

Which part requires a living organism?

I think they are being a little glib by saying a human is need to make the industrial processes.

Well, someone needs to treat the hydrogen sulphide with excess methanol over an aluminium oxide catalyst. I suppose a robot could do it...

For a non-life explanation, you're really looking for something that could plausibly happen in (abiotic) nature, not an industrial process.

The only thing that could make a nerd happier than detecting alien life would be detecting alien robots.

Wait, what's the difference?

Alien life could just be microbial, while alien robots would require an advanced technological civilization, I guess

Well, there could be nanobots...

Virtually all of them involve non-trivial design by sentient beings.

  Which part requires a living organism?
haha. Do you really need a hint?