They supposedly bought 50 acres ... that is a far cry from 5,000 to 7,000 acres.
Where did you come up with 600 - 1,000 gallons to the acre? That seems high to me.
This from Wikipedia. Feedstock yield efficiency per acre affects the feasibility of ramping up production to the huge industrial levels required to power a significant percentage of national or world vehicles. Some typical yields in US gallons of biodiesel per acre are:
Algae: 1800 gpa or more (est.- see soy figures and DOE quote below) Palm oil: 508 gpa[41] Coconut: 230 gpa[41] Rapeseed: 102 gpa[41] Soy: 59.2-98.6 gpa in Indiana[42] (Soy is used in 80% of USA biodiesel[43]) Peanut: 90 gpa[41] Sunflower: 82 gpa[41]
The Jatropha plant has been cited as a high-yield source of biodiesel but such claims have also been exaggerated. The more realistic estimates put the yield at about 200 gpa (1.5-2 tonnes per hectare).[46] It is grown in the Philippines, Mali and India, is drought-resistant, and can share space with other cash crops such as coffee, sugar, fruits and vegetables.[47] It is well-suited to semi-arid lands and can contribute to slow down desertification, according to its advocates.[48]