I guess this is a long shot..but seeing that the Bolte name is not a common name .....i would give this a chance..
I am researching my husbands family who came to Australia in the early 1900's or the late 1800's...I have not been able to find out a great deal..although i havent been researching this line for a long period...I do know that the family possibly came from the area of Frankfurt..I do have the area of Frankfurt as well...
I was told by an older memeber of the family that the Boltes were scattered to different countries when the decided to immigrate...and that certainly appears to be the case..

I am not sure what will be gained by my message..but i saw your notice quite by accident..when i was looking up a bridge actually that was named the Bolte Bridge here in australia...