This paper is excessively optimistic. The reason is that the energy efficiency values appear to be based on synthesizing saturated fatty acids. Fat that is in

This paper is excessively optimistic. The reason is that the energy efficiency values appear to be based on synthesizing saturated fatty acids. Fat that is intended for human consumption must consist mostly of the unsaturated oleic acid. Only a small proportion of saturated fatty acids is admissible besides the oleic acid. This is one of the few facts about human nutrition that can be considered as known to be true beyond any reasonable doubt. So after the synthesis of stearic acid by the path considered in this paper, an additional step for converting stearic acid into oleic acid is required. This step would be quite difficult when using non-enzymatic reactions, because the stearic acid must be dehydrogenated in a precise place and the reaction product must have a precise configuration around the double bond that is formed. Most likely it would have to be done by using a biological enzyme or using a culture of some bacteria or fungi. This additional step would reduce a lot the energy efficiency of the process in comparison with what is claimed in the paper. In the case when a culture of fungi or other fungus-like organisms would be used, like it is used now to produce oils rich in omega-3 fatty acids, then it is not clear whether converting artificially-synthesized stearic acid would be more efficient than producing an edible oil starting from a much simpler substance, like glycine or other such simple molecules, or from glucose produced by agriculture. For now, the prices of oils produced by cultures of microorganisms are several times higher than the price of the most expensive vegetable oil produced by agriculture (olive oil).