- explode: documentation ( source)
- trim: documentation ( source)
<?php
$date_start = '2017-06-08 00:00:00';
$ds = trim(explode(" ", $date_start)[0]);
echo "[" . $ds . "]";
$date = DateTime::createFromFormat('Y-m-d', $ds);
echo $date->format('d/m');
?>