The collapse of the ethanol boom continues as a Pratt-based ethanol producer is the latest to file bankruptcy. Gateway Ethanol LLC has filed for Chapter 11 bankruptcy protection, estimating it owes between $50 million and $100 million. The filing comes weeks after Minneapolis-based Dougherty Funding LLC sought to have Gateway placed in emergency receivership to preserve any money being returned to creditors. It moved to foreclose on the company’s plant in May, saying Gateway defaulted on a $54.3 million loan used to build the facility. In a motion field in the U.S. District Court of Kansas in September, Dougherty noted...