Enzymatic And Biochemical Constraints On The Utilization Of Terrestrially Derived Carbon

1256 Words Aug 24th, 2016 6 Pages
Enzymatic and biochemical constraints on the utilization of terrestrially derived carbon
The problem with using terrestrial derived carbon is not its energy content per se, but rather the accessibility of the energy contained within this material and the suitability of the biochemical composition of the resource for synthesis of new biomass in animals. Biological recalcitrance is due to kinetic, not thermodynamic, limitations. For example, a variety of terrestrial plants have average energy contents of 19 ± 1 MJ kg-1 (± 1 SD) (Friedl et al., 2005), which is slightly higher than for proteins and carbohydrates (i.e., 17 MJ kg-1), but considerably less than the average energy content of fats (38 MJ kg-1) and alcohols (29 MJ kg-1) (Blaxter, 1989). It is obvious that many synthetic organic compounds such as plastics have a high-energy content (20-46 MJ kg-1) while also being almost entirely resistant to attack by biological enzymes. Similarly, cellulose has extremely low bioavailability to the large majority of insects (Martin et al., 1991). True lignin digestion is thought to be restricted to a very small fraction of insects (Breznak & Brune, 1994; Geib et al., 2008). This is important because we hypothesize that aquatic animal consumers will grow best when offered diets that most closely match their own biochemical composition, or complement their endogenous capacity to modify and synthesize biochemicals.
Many bacteria are biochemical specialists and are equipped with specific…
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