dna sequencing - Is it possible to sequence only the 16S rRNA component? If so, how?

Basically, all 16S genes are highly conserved, i.e., they share much identical bases. This means one can bind the 16S gene piece (after DNA was cut) to a specific other piece of DNA, even if you don't know exactly the 16S gene bases. Everything else is discarded then. Now finally, using PCR the rest is amplified and sequenced. Sequencing 16S only is much less work, so that's how they did it years ago. Today, whole microbiomes are sequenced by professional labs.