According to his public profile, Frederico Navarro was a forty-odd years old Journeyman Mech Designer.
To be more precise, he was both a biotech expert and a biomech designer. This reflected the fact that every biomech designer had to know the ins and outs of exobiology, genetics, molecular biology, biomechanics and many other related fields.
How else could they design and 'grow' their biomechs if they didn't know how a living organism worked?
Biomechs may perform identical to classical mechs on the battlefield, but their organic nature meant that the logistics around them were completely different.
Mech companies didn't fabricate biomechs. They grew them. Biomechs literally started as tiny, juvenile masses of tissue. As long as they were kept in special cultivation pools, it usually took a couple of weeks or months for them to grow in size and mass.