As a mold remediator, I use Microbloc products.
- The formulations are VOC-free, water-based, and concentrated to be container-friendly as well.
- There are products to first treat and eliminate, then a product to treat the block and keep more mold from growing.
These products will need to be sprayed on with an airless sprayer, which can be rented at a big-box-type home improvement store.
I also would suggest running an air purifier in the basement 24/7. The systems I specify are used in military post remediation projects to keep the growth at bay.
For more information:
Read Ricky Cappe's Q&A "Can you recommend flooring for a basement that tends to get moldy?"