**Part 5**

**Experimental Techniques for the Evaluation of Stoichiometry** 

258 Stoichiometry and Research – The Importance of Quantity in Biomedicine

Yap, M. L., Mio, K., Ali, S., Minton, A., Kanamaru, S., Arisaka, F. (2010b) Sequential

Zhao L., Takeda S., Leiman, P. G., Arisaka F. (2000) Stoichiometry and inter-subunit

Zhao L., Kanamaru S., Chaidirek C., Arisaka F. (2003) P15 and P3, the Tail Completion

*Biochim. Biophys. Acta.* Vol.1479, No.1-2, pp.286-92.

pp. 808-813

1693-1700 (2003)

Assembly of the Wedge of the Baseplate of Phage T4 in the Presence and Absence of gp11 as Monitored by Analytical Ultracentrifugation. *Macromol. Biosci.* Vol. 10,

interaction of the wedge initiation complex, gp10-gp11, of bacteriophage T4.

Proteins of Bacteriophage T4, Both Form Hexameric Rings, *J. Bacteriol.* Vol. 185, pp.

**12** 

*Clermont-Ferrand* 

 *France* 

**Methodology for Bioprocess Analysis:** 

Farges Bérangère, Poughon Laurent, Pons Agnès and Dussap Claude-Gilles *Clermont Université, Université Blaise Pascal, Laboratoire de Génie Chimique et Biochimique,* 

**Mass Balances, Yields and Stoichiometries** 

The stoichiometry of a chemical reaction provides basic information about the nature and the quantities of chemical species consumed and produced. It also intrinsically contains all the information on transformation yields. Such information is useful and necessary for the design of any biotechnological process. In the case of microbiological reactions that support microbial growth, this information deals with the carbon and energy sources consumed, the terminal electron acceptor utilized, other metabolic products formed, as well as the quantity

In the first part, general mass balances principles/methodology for the stoichiometric analysis of a bioprocess will be presented. These methods will lead to stoichiometric coefficients estimation including statistical analysis and data reconciliation in case of redundant information. Redundant information means more information than the minimum required to calculate all the conversion yields with a suitable approach of mass balances; this concept of minimum information required is presented (degree of freedom or number of unknowns of the system); conversely over-determined systems, in the case of

In the second part, the previous stoichiometry principles will be applied to two practical examples. The first examined case is the continuous anaerobic cultures of *Fibrobacter succinogenes*. This strictly anaerobic bacterium was grown in continuous culture in a bioreactor at different dilution rates (0.02 to 0.092 h-1) on a fully synthetic culture medium with glucose as carbon source. Robustness of the experimental information is checked by C and N balances estimations. A detailed overall stoichiometry analysis of the process for each dilution rate examined, including all substrates and products of the culture, is proposed. The mass balances involved in stoichiometric equations were solved using data reconciliation and linear algebra methods in order to take into account errors measurements. In the last part, a second practical case,i.e. batch aerobic cultures of *Saccharomyces cerevisiae*, is presented. In this example, the bioprocess is analysed using different methodologies: (i) a

experimental data in excess, are associated to a statistical treatment.

**1. Introduction** 

of the biomass produced.
