Hello Keith,
I have some information on a Jacob Keller, which could possibly be your Jacob Keller. My great grandfather and mother traveled with a Jacob Keller and arrived in this country from the port of Bremen in 1853. I have the passenger list of the ship they were on. My grgrandmother was from Hockenheim, Baden, Germany and my grgrandfather from (I believe) Reilingen (a village about 3 miles from Hockenheim). Jacob and my grgrandparents were not relatives as far as I can tell, but he was from Hockenheim as was my grgrandmother. I'm not sure the ages match the Wyandot census - but this is the Jacob Keller I have info on (it matches the age on the ship's passenger list and I find my grgrandmother listed in the data set from the familysearch.org site as well)

From the familysearch.org database: I've gathered this info:
JAKOB Keller Pedigree
Male
Event(s): Birth:
Christening: 04 DEC 1831 Katholisch, Hockenheim, Mannheim, Baden
Parents:
Father: GEORG Keller Family
Mother: KATHARINA BARBARA DORST

From the Ship Agnes passenger list:
KELLER. Jacob, 22, Male, Laborer, Baden, Sandusky, Ohio
My grgrandparents:
FLECK, Juliane, 21, Female, None, Baden, Sandusky, Ohio (Juliane is wrong, her name was really Susanne)
VOGEL, Frantz, 24, Male, Tailor, Baden, Sandusky, Ohio

My grgrandparents stayed in Sandusky, OH for 3 months and then moved to Mansfield, OH for a few years and then to Upper Sandusky, Wyandot Co.

I think Jacob traveled around a bit too before settling in Upper Sandusky, Wyandot Co.

I have his biography too, but I will have to look for it. (you are in luck, I'm cleaning my basement tomorrow - maybe I will find it!) If I remember correctly, his biography mentions he traveled on the ship with my grgrandparents.

Unfortunately, I'm only a sporadic researcher and mainly have information that my late mother gathered, and unfortunately, its not in order.

Let me know if you think this is your Jacob or related to him, and I will post the passenger list in full (it is quite long.)