TOKYO, Nov 7 (Reuters) - Private equity fund Japan Industrial Partners has submitted a bid to buy Toshiba Corp (6502.T) for around $15 billion that lacks key commitments from banks, the Nikkei newspaper said on Monday, raising questions about whether the offer can succeed.JIP's proposal, which includes more than ten investors such as utility Chubu Electric Power Co Inc (9502.T) and financial services group Orix Corp (8591.T), is seen totalling around 2.2 trillion yen ($15 billion), with about 1 trillion yen of that coming from the investors, the Nikkei said.JIP's plan to allow Toshiba's current management to stay on after a buyout had raised alarm among some of Japan's big banks, whose funding is seen as critical to financing the deal, sources have said.Investor focus could now turn to another potential bidder, state-backed fund JIC, which sources have said is also preparing a bid.Private equity firm JIP and state-backed JIC had previously teamed up in a first-round of bidding for Toshiba earlier this year but then they parted ways for the second round."