By Jemima Kelly

LONDON (Reuters) - Ripple, a U.S. start-up which uses the blockchain technology that underpins digital currency bitcoin to help banks speed up their dealings with one another, has raised a further $55 million from investors, it said on Thursday.

The investors include Standard Chartered and Accenture, and take the total amount of money raised by the company so far to $93 million, it said, one of the largest sums raised by a blockchain start-up. Fellow San Francisco-based blockchain firm Coinbase has raised a total of $117 million.

Ripple offers banks a way to transact with each other directly using blockchain, without the need for an intermediary. Its backers including Marc Andreessen, one of Silicon Valley's best-known venture capitalists.

Blockchain technology - also known as distributed ledger or distributed financial technology - works as an electronic record-keeping and transaction-processing system, which requires no third-party verification.

Banks are increasingly investing in the technology, betting it will cut settlement times and make transactions faster, more reliable and easier to audit.

Total investment in blockchain over the past three years is approaching $1.5 billion, according to the World Economic Forum.

"This investment is part of our commitment to the bank's digitization agenda," said Standard Chartered's global head of transaction banking, Alex Manson. "Ripple is one of the most advanced distributed financial technology companies in the industry."

Spanish bank Santander said earlier this year it was using Ripple in a pilot program for staff who wanted to send money overseas.

The other investors in Ripple's Series B fundraising round included SCB Digital Ventures - the venture arm of Thailand's Siam Commercial Bank - and Japan's SBI Holdings.

Ripple also said it had added several new banks to its network, with banks such as Mizuho and National Australia Bank joining those already in its network, including UBS and UniCredit.

(Reporting by Jemima Kelly; Editing by Mark Potter)