TAIPEI, Sept 14 (Reuters) - Former Taiwan president Chen Shui-bian, known for advocating the island's formal independence from China, has appealed a guilty verdict and life sentence for graft, his office said on Monday.

The Taipei District Court on Friday convicted the two-term president on six charges related to corruption and bribery, closing a fractious, high-profile case that opened nearly three years ago, involving Chen's wife and numerous family members and aides. He was also fined T$200 million ($6 million).

Chen has said the charges were political and denied wrongdoing. "The high court's handling of the case must be fair, impartial and transparent," Chen's foundation said in statement announcing the appeal.

The case could affect support for Taiwan's opposition Democratic Progressive Party (DPP), which backed the former president when he was in office and faces tough local elections at the end of the year. Chen left the DPP last year.

Prosecutors had charged Chen with embezzling T$104 million ($3.185 million) from a special presidential office fund, accepting bribes of about $9 million related to a land procurement deal and taking another $2.73 million in kickbacks to help a contractor win its bid for a government project.

While ruling from 2000-2008, Chen upset Beijing and the United States by advocating formal independence from China, which has claimed sovereignty over the self-ruled island since the end of the Chinese civil war in 1949.

Chen's wife, Wu Shu-chen, was convicted on seven counts of graft and also sentenced to life in jail. She was fined T$300 million. Chen's son and daughter-in-law were handed sentences ranging from 20-30 months for related crimes.

The ex-president will qualify for a lighter sentence if he behaves well in prison, a district court spokesman said.