explode

$number= "0 (532) 588 72 41
DRN OTO KİRALAMA,0 (535) 730 06 99
CENTER RENT A CAR,0 (534) 560 81 81
İSTANBUL RENT A CAR,0 (530) 855 13 41
ARENA RENT A CAR,0 (530) 306 06 39
FULL CİTY TRAVEL,0 (554) 170 87 44
OBIDO RENTAL CAR,0 (538) 442 44 63";

echo $metin= (filter_var($number, FILTER_SANITIZE_NUMBER_FLOAT,
FILTER_FLAG_ALLOW_FRACTION));

//Çıktı: 05325887241053573006990534560818105308551341053030606390554170874405384424463

$liste = "DRN OTO KİRALAMA,0 (535) 730 06 99
CENTER RENT A CAR,0 (534) 560 81 81
İSTANBUL RENT A CAR,0 (530) 855 13 41
ARENA RENT A CAR,0 (530) 306 06 39
FULL CİTY TRAVEL,0 (554) 170 87 44
OBIDO RENTAL CAR,0 (538) 442 44 63";

$metinler = explode("n", $liste);
foreach ($metinler as $anahtar => $metin) {
    list($firma,$numara) = explode(",", $metin);
    $numara = str_replace("r", "", $numara);
    $numaralar[] = $numara;
}

print_r(implode(",", $numaralar));