* Company has struggled to ramp up protein production
* Shares have lost most of their value this year
Nov 15 (Reuters) - Shares of BioExx Specialty Proteins BXI.TO plunged on Tuesday, after a research firm cut its rating on the Canadian agribusiness company one day after it posted a bigger quarterly loss.
Fraser Mackenzie cut its rating for BioExx to "underperform" from "market perform" after the company reported a C$5.75 million ($5.64 million) third-quarter loss after markets closed on Monday. That compared with a loss of C$3 million in the year-earlier quarter.
BioExx shares slumped 12 Canadian cents, or 44 percent, to 15.5 Canadian cents in Toronto on Tuesday morning, continuing a slide that has seen the stock lose nearly all it value this year, after touching a 52-week high of C$2.71.
The company, which crushes the oilseed crop canola to produce proteins suitable for human consumption, used in products such as sports drinks, has struggled over the past year to scale up production at its plant in Saskatoon, Saskatchewan.
BioExx also said on Monday it has promoted Chris Schnarr to chief executive and approved a shareholder rights plan to give shareholders and directors time to consider any takeover bid.
Schnarr was previously chief financial officer and had acted as interim CEO after Chris Carl was asked to step down in August.
Schnarr said BioExx will look to firm up its business at current production levels and look for partnerships.
The company also appointed Greg Furyk to chief financial officer from his previous role as the company's controller.
$1=$1.02 Canadian Reporting by Rod Nickel; editing by Rob Wilson