What type of Bacteria?
Consolidating my comments, and taking all the results at face value (though microbiology can be very tricky), the most likely candidates are Moraxella, or Neisseria spp.
Gram negative cocci (spherical cells) rules out a large number of possibilities, leaving just the above 2 and Veillonella as candidates.

The OP said that the culturing was done under aerobic conditions at 30˚C. Veillonella is an obligate anaerobe, and so wouldn't survive this. Both Moraxella and Neisseria are happiest at 37˚C but would no doubt grow at 30. Both are cultivable on blood agar. Neisseria is best cultured in a 5% CO2 atmosphere, so is probably somewhat less likely. Both appear as pale-whitish colonies on plates. The OP's observation of yellowish colouring could be artifactual of the plate colouring, I'm not 100% sure.
Both are positive for oxidase and catalase.
Neisseria on blood agar:

Moraxella on blood agar:

One final comment: both of these are pathogens, so continue with all due caution.
Moraxella, in particular, is a respiratory pathogen, so I would advise working in a biosafety cabinet. I'll assume you already have the relevant paperwork/permission to be handling &gt; BSL1 organisms...