* Brent oil falls more than 1 pct, giving up Tuesday's gains
* Gold drops for fifth day in six; copper slides ahead of China holiday
* Grains decline before USDA report on Friday
* Coming Up: Aug U.S. durable goods orders; 1230 GMT
By Jane Lee
SINGAPORE, Sept 28 Commodities fell on Wednesday, giving up their biggest daily gain in more than six months racked up the previous day, as investors flocked to the U.S. dollar on concern data may signal slowing economic growth.
Doubts over Europe's commitment to its plan to expand a rescue fund also caused the dollar to strengthen against the euro, making gold, copper, grains and crude oil more expensive for buyers paying in other currencies.
"There are still a lot of fears over Europe," said Ken Hasegawa, a commodities derivatives manager with Newedge Brokerage in Tokyo.
Markets are watching for U.S. durable goods orders for August, due later on Wednesday, which a Reuters poll estimated would be flat following a rise of 4.1 percent in July. .
The 19-commodity Reuters-Jefferies CRB index rose 2.7 percent on Tuesday in its biggest daily gain in more than six months.
Hurdles Greece faces in its attempt to avoid bankruptcy and disagreements among euro zone nations have sparked concern among investors that growth won't recover anytime soon.
An audit team from the European Union, European Central Bank and the International Monetary Fund is expected to start arriving in Athens on Wednesday and begin talks the day after on the Greek government's plan to deepen budget cuts and raise new taxes.
Data on Tuesday showed that Americans worried about their incomes as they struggled to find work in September, holding consumer confidence near 2-1/2-year lows and pointing to weak spending in the months ahead.
Brent crude futures LCOc1 lost $1.21 to $105.93 a barrel by 0539 GMT. U.S. crude CLc1 shed $1.56 to $82.89 a barrel. Oil prices jumped more than 3 percent on Tuesday.
Brent is poised to fall 5.5 percent in the third quarter, according to Reuters market analyst Wang Tao.
That's the second quarterly decline, and the steepest since the three months ended June 2010. U.S. crude is set to lose almost 13 percent this quarter, its largest drop since the fourth quarter of 2008.
Precious metals were also pushed lower, after gains in the past few months prompted investors to take profit as risks of slower growth persist.
Spot gold fell $11.91 to $1,636.99 an ounce, down for a fifth day in six. It had tumbled to a two-month low of $1,534.49 on Monday -- down from a lifetime high around $1,920 an ounce struck in early September.
Three-month copper on the London Metal Exchange fell 3.3 percent to $7,345 a tonne, after surging 4.5 percent in the previous session. That was its biggest jump in 19 months.
Market players said Shanghai copper prices were supported by a surge of speculative activities before a week-long national holiday starting early October.
"The holiday is coming up and everyone is out to make a quick buck before that," Zhou Jie, an analyst at CIFCO Futures, said in Shanghai.
"The shorts are closing positions, locking in profits, while others are doing arbitrage plays -- buying copper on Shanghai and selling on London."
USDA STOCKPILE REPORT
Grains also fell, with investors looking to the U.S. Department of Agriculture's quarterly stocks report on Friday for signs that consumption may wane.
Wheat for December fell for the first day in four, easing 0.5 percent to $6.54-3/4 per bushel. Declines were limited by concern that drought may hamper seeding of U.S. winter wheat crop, traders said.
Soy for November lost 0.9 percent to $12.52-1/4, headed for a second quarter of declines.
Corn for December fell 0.8 percent to $6.47-1/4 per bushel, erasing Tuesday's gains. The grain has risen 2.9 percent this year, compared with declines in soy and wheat.
"There are expectations that the USDA may report a larger-than-expected supply on corn," said Lynette Tan, a grains analyst at Phillip Futures in Singapore.
"In the past week, the fall in grains is due to macro-economic issues, with people worried about a slowdown in growth and the crisis in the euro zone. Usually, when macro sentiments are strong, investors tend to ignore the fundamentals." (With additional reporting by Francis Kan, Lewa Pardomuan and Carrie Ho; Editing by Clarence Fernandez)