Or, if they're in a forgiving mood, this will produce one e-mail address per line, regardless of delimited position, (assuming the founders were already on separate lines):
| sed -E 's/^.*[^[:alnum:]\._\-]([[:alnum:]\._\-]+@[[:alnum:]][[:alnum:]\-]+\.[[:alnum:]][[:alnum:]\-\.]*)[^[:alnum:]\-\.].*$/\1/'
| grep -E '^[[:alnum:]\._\-]+@[[:alnum:]][[:alnum:]\-]+\.[[:alnum:]][[:alnum:]\-\.]*$'
