By Marcelo Teixeira NEW YORK (Reuters) -Mercon Coffee Group, one of the world’s largest coffee traders, has filed for bankruptcy protection in the U.S. due to what it defined as “exceptionally challenging operating environment,” according to a document seen by Reuters. Mercon, which has operations in all the major producing regions including Brazil, Vietnam and Central America, said in a letter sent to clients that problems in recent years such as the logistical disruption during the pandemic, frost and drought in Brazil, price volatility, and rising interest rates all combined to hurt the com…