how anoxybiont choose the pathway

[warmpenguin]

There are many anaerobes which choose to obtain energy from glycolosis. There are two products from the pyruvate, one is alcohol like the yeast, and the other one is lactic acid like the lactobacillus. My question is that what‘s the evolution of choosing these two pathways to generate energy. What is the factor for its choosing the alcohol pathway or the lactic acid pathway?

I have made some guesses.

1). The pathway the organism chooses was determined by the environment it was living in. The product, alcohol or lactic acid, can have the function of inhibiting the growth of other organisms in the same living environment.

2). The product can be used as other organisms’ feeding, thus making a symbiosis system.

Hope someone can give me some information about that. Thank you!