Promptly after the order for relief under this chapter, the United States trustee shall appoint one disinterested person that is a member of the panel of private trustees established under section 586(a)(1) of title 28 or that is serving as trustee in the case immediately before the order for relief under this chapter to serve as interim trustee in the case.

If none of the members of such panel is willing to serve as interim trustee in the case, then the United States trustee may serve as interim trustee in the case.