In a deep saute pan, cook the bacon over medium heat to render the fat until it just begins to crisp. When it does, add the bison, crumbling with a wooden spoon. Brown nicely, then add the onion, celery, and carrot and cook until soft, about 3-4 minutes. Add the garlic and cook for 30 seconds or so, then add tomato paste and cook for another 30 seconds, stirring. Add the white wine, bring to a simmer, and reduce by about half. Then add the broth and simmer for about 30 minutes. Season well with salt and pepper. Bring a large pot of salted water to a boil and cook the pasta to al dente. Toss in the sauce and add butter. Mound into a shallow bowl and top with lots of freshly grated Parmesan cheese.