Lactococcus lactis subsp. cremoris This is a combination of two common forms of mesophilic and homofermentative cultures. These microorganisms are lactic acid bacteria, Gram-positive, and acid-resistant. They produce lactic acid during fermentation. They grow best in microaerophilic conditions (2-10% oxygen). Lactococcus delbrueckii subsp. lactis Lactococci are fermenters that derive their