The idea of using enzymes is a brilliant one. However you have got to ask a few questions.
How much is the use of enzymes really going to improve your yield?
Is the price of some of the enzymes really worth it?
Also, you mentioned pectolase, it is used in homebrewing to mainly to reduce pectin hazes. Basically it breaks down the insoluble pectin molecules that produce a haze in wines and some ciders. however, pectin is mostly found in the fruits of plants, not in their roots, as a result the use of pectin on MHRB would be needless.
You also raised the point of using cellulase, which I think could be quite useful as it will break the MHRB down to allow more goodies to be extracted.
However a problem that will have to be addressed, is that enzymes need to be at an optimum pH and temperature to work. For cellulase: 40-60ºC and a pH between 4 & 5. This seems to be a lot of effort and for the increase in yield that you would be gaining, it does not seem worthwhile
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