FILE PHOTO: Thyssenkrupp's logo is seen close to an elevator test tower in Rottweil, Germany, September 25, 2017. REUTERS/Michaela Rehle/File Photo

FRANKFURT (Reuters) - Lanxess LXSG.DE Chief Executive Matthias Zachert is not available to become CEO of Thyssenkrupp TKAG.DE, a source familiar with the matter said, ending speculation that he could replace interim CEO Guido Kerkhoff.

Zachert, who was seen as a potential candidate for the CEO job at the German conglomerate, had only in May renewed his contract at Lanxess until 2024.

The future of the chemicals group is very important to Zachert, the source said. Zachert has been CEO of Lanxess since April 2014.

Lanxess was not immediately available for comment.

The unavailability of Zachert cuts short the list of potential candidates for the top job at Thyssenkrupp, which lost its CEO and chairman in July, causing turmoil at the elevators-to-submarines group.

Investors, most notably activist fund Elliott which owns shares in Thyssenkrupp, have called for an external CEO to lead the group. Kerkhoff, who was finance chief before taking the helm after Heinrich Hiesinger’s sudden departure as CEO, will remain in the job until a permanent successor is found.

Other executives seen as potential candidates for Thyssenkrupp's CEO job include former finance chief Stefan Kirsten and former Siemens SIEGn.DE board member Siegfried Russwurm.