Please take a general biology class and a microbiology class.
I have, thanks. And one or three on genetics, chemistry, zoology, etc.
1. Dust Eating Bacteria: Dust comes from many sources with the majority coming from skin cells. Think about that for a second.
Skin cells, plant cells, dirt, you name it. What it all is, is raw materials. Break it down and you have proteins and minerals. Both of which can be used by an organism for fuel and growth. Take that organism and design it in a way to use those specific minerals and proteins, and return a specific chemically-based odor. So, design a microorganism that has multiple digestive systems, one main system, one aimed at proteins and one aimed at minerals. The main system divides the the raw material into proteins and minerals, then the other two breaks down their specific target nutrient accordingly, converting them into chemical odor. Does this exist now? No. But that's the whole point, once we have a catalog of building blocks, the potential for creating something like this is well within the realm of possibility.
2. Digesting other foods takes more than just bacteria to get the required nutrients
Currently, yes. But being able to design organisms to specifications can change that. Again, technology like this can allow us to move far beyond what is known today. And it doesn't have to be just one organism, either. There could be one organism that breaks down a substance in one way, and two other organisms that then break those resultant components into easily digestible material. The point is, being able to design new organisms removes the dependency on existing systems and allows us to experiment in directions that we never would have thought before.
3. Ask yourself why animals never photosynthesize. Could it possibly be because it is such an inefficient process to meet the energy requirements of the moving animal?
So what if it is inefficient? If it is SUPPLEMENTAL to our existing energy systems, then it is beneficial as it would reduce the amount of traditional energy consumption needed. And who's to say that it would be inefficient? Sure, in the current method used in plants, it would be. But who's to say that we have to restrict ourselves to just that methodology? Maybe there are alternative methods that could be tapped into that would yield higher energy results. Again, the point is, the POTENTIAL is there, and in a form that we have never been able to attempt before.
Education takes effort!
Yes, it does. But vision and thinking outside the box takes far more effort. My statements were not to say that current organisms could do any of that, but through building our own organisms, testing them, refining them, etc., all of these concepts are possible, once we remove the assumptions that we have to restrict these organisms to that which already exists.