as noted earlier, setting bash variables does not allow whitespace between the variable name on the LHS, and the variable value on the RHS, of the '=' sign.
awk can do everything and avoid the "awk"ward extra 'grep'. The use of awk's printf is to not add an unnecessary "\n" in the string which would give perl-ish matcher programs conniptions. The variable/parameter expansion for your case in bash doesn't have that issue, so either of these work:
variable=$(ps -ef | awk '/port 10 \-/ {print $12}')
variable=`ps -ef | awk '/port 10 \-/ {print $12}'`
The '-' int the awk record matching pattern removes the need to remove awk itself from the search results.