Elemental Composition of Biomass and its Relation to Energy Content, Growth Efficiency, and Growth Yield

Biomass synthesis from primary substrate is a principal feature of growth. A short-cut method for the determination of growth yields and efficiency is presented. Elemental analyses of the products (individually or collectively) permit one to calculate directly and simply the amount of substrate carbon and electrons which are conserved, and thus the amount of substrate required, and the respiratory gas exchanges associated with the synthesis. Glucose is taken as a standard substrate with the required amount termed Glucose Equivalent (GE, mol mol−1) or Glucose Value (GV, g g−1). Comparisons of GV with Production Values (PV) calculated from biochemical pathways (Penning de Vries, Brunsting and van Laar, 1974) show that PV = 0.88 ±0.01 GV. The glucose requirement also serves as a close predictor of the heat of combustion of the product.