One of the major goals of modern astrophysics is to understand the formation of 
our Solar System. Since low-mass protostars are suns in the making, the study 
of these objects and their environment provides one of the best ways to 
investigate the Sun's formation process and to peek in the past history of our 
Solar System. My research focuses on the chemistry occuring in Class 0 sources 
(the earliest known phases in the evolutionary scenario of low-mass protostars) 
by studying complex organic molecules in their envelopes. Such molecules have 
been discovered in IRAS16293-2422, the prototype of Class 0 sources, proving 
the existence of hot corinos, the inner regions of the protostellar envelope 
where the icy grain mantles sublimate. Some of these molecules have also been 
observed in comets in our Solar System, raising the question of whether (and if 
so, how) the chemistry of Class 0 objects affects the chemical composition of 
the protoplanetary disk material from which comets and other planetary bodies 
form. However, it is first necessary to determine whether hot corinos are 
ubiquitous in low-mass protostars or if IRAS16293-2422 is an exception. In this 
talk, I present the steps I took to search, find and characterize other hot 
corinos, using the IRAM-30m and PdBI.
I also confront  the possible formation pathways with the results of my 
observations to try and discriminate whether complex organic molecules form via 
gas-phase or grain-surface reactions. Although it was not possible to arrive at 
a definite answer, my data seem to favor the later formation route. Moreover, 
the comparison of hot corinos and their high-mass analogs, the hot cores 
(showing that complex molecules are relatively more abundant in hot corinos), 
also support grain-surface synthesis of these molecules.
Finally, I will mention the research projects I am currently working on at the 
Leiden Observatory.