Improving biofuel production and distribution

The current hot biofuel is ethanol, but ethanol has some down sides. Now the biggest is that yeast can only ferment simple sugars, and the cheapest biomass money can buy is cellulose and unfermentable. However, that angle is largely being dealt with transgenic yeast, so I won't cover that asspect. The biggest problems that remain are that distillation of the ethanol, which uses lots of energy, and ethanol can’t be disturbed by pipeline, so it needs to be used close to the source to be practical. This means either locally grown grain must be used to produce the ethanol, but not every part of the country grows fermentable grain. This means the grain must be shipped however, if the Whiskey Rebellion taught us anything, it taught us that it is cheaper to ship the booze then it is to ship the grain. (Even in bulk carriers by train.) Thus it seems like good idea to find a way to solve both those problems in a single step, and that step is ethane or ethene. By engineering the yeast to either reduce the ethanol to ethane or dehydrate it to ethane, both of which are gases, continuous fermentation would become possible, since distillation wouldn't be required. Currently most ethanol production is batch or semi-batch since you want to get ethanol as high as possible to reduce the amount of distillation required, but the ethanol poisons the yeast. However, both ethane and ethane are gases, so they would bubble out of the fermentation tank, so they wouldn’t poison the yeast, so you just keep adding raw material and removing waste, at the process keeps going.
The collected ethane/ene can be compressed, and/or liquefied for pipeline transport using the existing natural gas infrastructure, to anywhere in the world. Once at the destination if ethanol is required product the ethane/ene gas can be converted using catalysts back to ethanol. Since the ethane can be co-minged with regular natural gas it can be stored underground, or used as feed stock for chemical production. Imagine the oxymoron and pun of "green" vinyl!
However, the more interesting prospect is using the ethane as bio-natural gas to fuel buses and fleet vehicles. Better yet for passanger cars, you have a hybrid car that was hybrid fuel too. Instead of carrying around 126 lbs of gasoline (with gasoline weighing 6 lbs a gallon and the car having a 21 gallon tank), you have 20 pounds of bio-ethane, just to make your daily commute, (bio-ethane is carbon neutral) and a 200 lb cylinder at home that charges your tank at night. That way if you need to drive long distance you can use regular gasoline, but most of the time the tank sits empty, and you burn a clean fuel.