Could you please re ask the question as it is not possible to get the exact meaning of what you want to know.

how can ethanol that is polar compounds pass through the membrane while the membrane is polar and non-polar compound if it transport by diffusion? Are there other mechanisms or regulation? like water through the membrane by integral protein (aquaporin)

Anaerobic respiration takes place in the fluid portion of the cytoplasm whereas the bulk of the energy yield of aerobic respiration takes place in the mitochondria. Anaerobic respiration leaves a lot of energy in the ethanol, that the cell cannot use and must excrete.so cell excrete ethanol through ethanol transporter.

And one more thing, ethanol never excreted alone it always together with glycerol, acetic acid through transporter proteins.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1082793/

go through this paper.

Yeahh, it's make sense, if there is transporter protein. would you show me the journal or other literatures that explain about excreted ethanol regulation from cell? 

Thank you so much anyway

thank you

Information about  organelles, metabolic pathway and transport system or excretion of ethanol by  S. cerevisiae can be found in books and/or reviews on Yeast Physiology; Alcoholic Fermentation. Ex.: Walker, G. M. (1998). Yeast physiology and bitechnology. Scotland: John Wiley & Sons.

thanks Alessandro

Ethanol is a more or less small polar compound that can pass through the cell membrane aqueous channel