Review Article

Computational Approaches for Microalgal Biofuel Optimization: A Review

Table 4

A comparative table contrasting major constraint based modeling tools (adapted from Blazier and Papin 2012 [53]).

GIMMEiMATMADEE-FluxSIMUPMTA

DescriptionDetermines sets of active versus inactive reactions comparing expression levels to a set threshold optimizing the model towards a set objective functionCategorizes reactions into high, moderate, and low expression and solves mathematical equation to optimize for an objective functionEstablishes a differential expression profile using several datasets originating from different growth conditionsSets upper bounds for lowly expressed reactions using an externally set threshold to evaluate expression data setsIdentifies bioengineering strategies that force the cell to coutilize substrates achieving a state of “synthetic survival”Predicts gene knockout strategies that would alter the metabolic fluxes in a cell in order to achieve the objective function assumed

AdvantagesRequires one set of expression dataRequires no knowledge of metabolic functionsRequires no externally set threshold for expression levelsRequires no reduction of expression data to an on/off categorizationAchieves the coutilization of two sugarsCategorizes cell metabolism as “source” or “target” with no necessary a priori knowledge of functionalities

DisadvantagesRequires an externally set threshold for mRNA transcript valuesCategorizes genes into high, moderate, and low expressionRequires more than one dataset of expression data to establish differential expression profilesSets an upper bound on fluxes using a specific function converting expression dataSo far only applicable to sugars Requires gene expression profiles in order to identify knockout strategies