Simulated concentration gradients in capsules. Simulated concurrent local concentrations of glucose, xylose, furfural and 2-hydroxymethylfurfural (HMF) at steady state in liquid core capsules half-filled with cells, calculated using finite element modelling in 2D axisymmetrical geometry and base case parameter values. Reactions occurred only in the cell pellet in the lower half of the capsule. Numbers are in mmol/l. The maximum values were equal to the concentrations in the surrounding medium. For details, see Materials and Methods.