The article says the cost of feeding one astronaut for one year is around 5,000-160,000 tons of ore per year. My understanding is the rule of thumb is about an order of magnitude nutritional drop off each step - that is, to produce 100cal of meat requires 1000cal of plant food. Bumping those yield estimates, especially the pessimistic end, up by another factor of 10 is just a phenomenal amount of material to process for one person for one year.
I didn't read the paper in depth, just skimmed it, but it seems like their assumption is that the astronauts will be eating some sort of microbe slurry; so I think that the cost includes only that, not using microbes to feed higher-order life or growing plants.
Agree, but the post I was responding to was suggesting it be used as an agricultural feedstock to feed things the astronauts eat - that’s where my order-of-magnitude calculation came from.
Biomass is recycled. You would only need the replacement rate for losses, which would be nonzero not negligible, but much smaller.
That's just the mass you need to extract the resources that make up the food that one person consumes in a year. Assuming you don't just space the human waste and instead reuse it you'll be accumulating material that can make up the biomass that will comprise a large and intricate food web that will eventually make up the biomes of large O'Neill cylinder stations.