grep pattern exacly matching from file and search only in first column

You probably want the -wflag - from man grep

   -w, --word-regexp
          Select  only  those  lines  containing  matches  that form whole
          words.  The test is that the matching substring must  either  be
          at  the  beginning  of  the  line,  or  preceded  by  a non-word
          constituent character.  Similarly, it must be either at the  end
          of  the  line  or  followed by a non-word constituent character.
          Word-constituent  characters  are  letters,  digits,   and   the
          underscore.

i.e.

grep -wFf patfile file
denovo1 xxx yyyy oggugu ddddd
denovo22 hhhh yyyy kkkk iiii

To enforce matching only in the first column, you would need to modify the entries in the pattern file to add a line anchor: you could also make use of the \b word anchor instead of the command-line -w switch e.g. in patfile:

^denovo1\b
^denovo3\b
^denovo22\b

then

grep -f patfile file
denovo1 xxx yyyy oggugu ddddd
denovo22 hhhh yyyy kkkk iiii

Note that you must drop the -F switch if the file contains regular expressions instead of simple fixed strings.

one can use awk too:

awk 'NR==FNR{a[$0]=$0}NR>FNR{if($1==a[$1])print $0}' pattern_file big_file

output:

denovo1 xxx yyyy oggugu ddddd
denovo22 hhhh yyyy kkkk iiii