The detection of molecular lines toward low-mass stars that are currently forming tells us about the physics, dynamics, and chemical richness of these regions. The Perseus ALMA Chemical Survey (PEACHES) targeted 50 Class 0/I sources and multiple molecular transitions, like simple molecules such as CS, SO, C2H, and more complex ones, such as CH3OH and CH3CN. The sample comprises sources within a range of bolometric temperatures and luminosities. 

I will present the observations of sulfur-bearing species (CS, SO, 34SO, and SO2) and compare them with literature data, where other simple and complex species are observed toward the same sources. In addition, sources with very low luminosities, potencial precursors of brawn-dwarfs, show very weak emission of S-bearing species and present a significant lack of emission lines. This makes low luminosity sources very challenging to study and to detect.

Finally, I will conclude with recent JWST observations that suggest that proto-brown dwarfs are rich in hydrocarbons, setting the stage for future ALMA observations.