Something like this?

#! perl -slw
use strict;

while( <DATA> ) {
    chomp;
    s[^(\QThe seller has the following *fruit*\E types:)(.+)$]{
        my($const, $rep ) = ( $1, $2 );
        $rep =~ tr[* ().][#]d;
        $rep =~ s[,\s*and][and];
        "$const*($rep)*."
    }e;
    print;
}

__DATA__
The seller has the following *fruit* types: ( *apples* , *oranges* , *
+pears* , *berries* , and *mangoes* ).
The seller has the following *fruit* types:  *apples* , *oranges* , *p
+ears* , *berries* , and *mangoes* .
The seller has the following *fruit* types: ( *apples* , *oranges* , *
+pears* , *berries*  and *mangoes* ).
The seller has the following *fruit* types:  *apples* , *oranges* , *p
+ears* , *berries*  and *mangoes* .
[download]

Output:

c:\test>785401.pl
The seller has the following *fruit* types:*(#apples#,#oranges#,#pears
+#,#berries#and#mangoes#)*.
The seller has the following *fruit* types:*(#apples#,#oranges#,#pears
+#,#berries#and#mangoes#)*.
The seller has the following *fruit* types:*(#apples#,#oranges#,#pears
+#,#berries#and#mangoes#)*.
The seller has the following *fruit* types:*(#apples#,#oranges#,#pears
+#,#berries#and#mangoes#)*.
[download]