Methanol induction systems are conventionally used in Komagataella phaffii to achieve high recombinant protein titers. However, methanol is toxic for the cells and leads to high cell stress which potentially hinders recombinant protein production. To overcome this bottleneck, bi-directional promoter systems can be used to perform co-expression of the target protein and a helper protein (chaperone) in parallel allowing methanol-free recombinant protein production leading to a sustainable processes