A unit of real-estate company Blackstone Inc. is acquiring a sprawling life-sciences and office campus in Boulder, Colo., the latest sign that the city at the base of the Rocky Mountains is emerging as a hub for the biotechnology and pharmaceutical industries. Blackstone’s BioMed Realty Trust Inc., a real-estate owner that focuses on life science and tech buildings, is paying more than $600 million for Flatiron Park, a 22-building complex. BioMed Realty plans to invest another $200 million in the property, in part toward converting traditional office space to labs targeted at new and existing Boulder life-sciences companies.