Poly-Lactic Acid (PLA) is a bio-based polymer composed of lactic acid units. Its advantages compared to traditional fossil based polymers are not only its production from renewable sources, but also its characteristics such as biocompatibility, which allows PLA to be used from food packaging to biomedical applications. Current lactic acid production is carried by fermentation of carbohydrates. However, the bacterial production has increased costs due to nutritional needs, pH correction and downstream processing. All those factors can be overcome by the adoption of acid tolerant yeasts such as Pichia pastoris. In the present study, we have successfully transformed GS115 strains of P. pastoris with exogenous Lactate Dehydrogenase (LDH) from bacteria. Our goal is to assess LDH expression and analyse the formation of L-lactic acid in minimal medium, in consonance with our recent publications.