CBOT December corn settled up 1/4 cent at $3.45-1/4 per bushel after dipping lower near the close.
US markets will be closed on Thursday for Thanksgiving, with CBOT trade resuming Friday at 8:30 a.m. CST (1430 GMT).
The US Energy Information Administration said weekly US output of corn-based ethanol rose to a record 1.074 million barrels per day, while stocks of the biofuel rose to 21.9 million barrels.
Friday is the last trading day for CBOT December options, and traders noted sizable open interest in puts and calls at the $3.50 and $3.40 strikes.
Ahead of the US Department of Agriculture's weekly export sales report, which is delayed until Friday, analysts expected the government to report corn export sales at 900,000 to 1.4 million tonnes (old- and new-crop years combined).