Special Abstracts / Journal of Biotechnology 150S (2010) S1–S576 S525

the entrance into S phase (PS). These values are nutritionally modu-lated: higher growth rates and larger PS are observed in rich media.The aim of this line of work is first to generate a coarse-grain scaffoldmodel of growth and cycle (GCM) and then to utilize new experi-mental findings and the previously described network analysis toachieve a finer-grain modeling of specific modules of GCM. Itera-tively improved hybrid models for yeast growth and cycle wouldthus be achievable.

doi:10.1016/j.jbiotec.2010.09.843

[P-S.37]

Equation for predicting shelf life of an apple

Ajit BHosale 1,∗, K.K. Sundaram 2

1 Cummins College of Engineering for Women, Pune, India2 Vishvakarma Institute of Technology., IndiaKeywords: Shelf Life; Firmness; Respiration rate

The shelf-life of a Fruit is critical in determining both its qualityand profitability. Everyone benefits from healthy produce. Approxi-mately Rs.105Cr {$200million} is lost each year due to waste causedby post harvest diseases, poor temperature management, bruisingand other factors. This paper focuses in general on broadly defin-ing a philosophy for predicting life of plant food and in particularattempt to predict the shelf life of apples. Earlier attempts are madeto predict shelf life in terms of firmness or atmospheric conditions.Quality of apple can be evaluated against colour or sugar contentsetc.

Presented in this paper is a mathematical relationship predict-ing the shelf life of an apple. An apple is not dead at the time ofharvest. It remains a living, respiring organism and continues totake in oxygen and give off carbon dioxide and another gas, ethy-lene. Since the apple is no longer receiving nutrients from thetree but is still respiring, it must use up the food it has storedover the growing season. The low temperature, high humidity, andexchange of gases through air circulation serve to slow those natu-ral events as much as possible. Our study quantitatively takes in toaccount parameters such as firmness, colour of apple, atmospherictemperature, and respiration rate. This fundamental equation couldbe potentially used by farmers, food malls, and big food chains. Thisrelationship can be extended to predict shelf life of perishable fruits.

doi:10.1016/j.jbiotec.2010.09.844

[P-S.38]

Effective synthesis of methyl (R)-mandelate by asymmetricreduction with a thermophilic NADH-dependent alcohol dehy-drogenase

A. Pennacchio 1,∗, A. Giordano 2, M. Rossi 1, C.A. Raia 1

1 Istituto di Biochimica delle Proteine, CNR, I-80131 Naples, Italy, Italy2 Istituto di Chimica Biomolecolare, CNR, I-80078 Pozzuoli, Naples,Italy, ItalyKeywords: Asymmetric biocatalysis; Coenzyme regeneration;Dehydrogenases/reductases; Chiral alfa-hydroxy ester

Dehydrogenases/reductases (ADHs) are nowadays among themost requested enzymes used for the preparation of opticallyactive compounds, for the inherent advantages over chemocata-lysts in terms of their high chemo-, enantio-, and regioselectivityas well as to be environmentally friendly (Kroutil et al., 2004). AnNAD(H)-dependent, highly enantioselective ADH (TtADH), identi-

fied in the eubacterium Thermus thermophilus HB27, was purifiedand characterized in our laboratory (Pennacchio et al., 2008). Thethermophilic enzyme catalyses the following reactions at 1–3 mgscale with high yield conversion: the reduction of acetophenone,2,2,2-trifluoroacetophenone, �-tetralone, and �-methyl benzoyl-formate (MBF) to (S)-1-phenylethanol (>99% enantiomeric excess,ee), (R)-�-(trifluoromethyl)benzyl alcohol (93% ee), (S)-1-tetralol(>99% ee), and methyl (R)-mandelate (R-MM) (91% ee), respec-tively. Noteworthy, the optically active alcohols produced are usedas valuable chiral building blocks in organic synthesis (Kroutil etal., 2004; Pennacchio et al., 2008).

To demonstrate the preparative applicability of TtADH wefocused on the chemoenzymatic synthesis of MBF to R-MM. Twoin situ NADH-recycling systems based on the enzyme-coupledapproach were developed: the first system included a thermophilicNAD(P)-dependent glucose dehydrogenase and glucose, and thesecond system involved a thermophilic NAD(H)-dependent ADHfrom Bacillus stearothermophilus and an alcohol substrate as hydro-gen donor. The effects of various parameters on the asymmetricsynthesis such as pH, temperature and reaction time, agitationspeed, solubility, enzymes and cofactor stability, substrate andproduct inhibition, and tolerance to organic solvents were eval-uated. Both recycling systems proved to be highly efficient andenantioselective in producing R-MM with 95-93% ee, 98-99% con-version and 74–76% isolated yield when reduction of the keto esterwas scaled up to 0.2–0.5 g under established optimal conditions.

This work was funded by the ASI project MoMa 1/014/06/0 andby FIRB grant RBNE034XS.

References

Kroutil, K., et al., 2004. Curr. Opin. Chem. Biol 8, 120–126.Pennacchio, A., et al., 2008. Appl. Environ. Microbiol 74, 3949–3958.

doi:10.1016/j.jbiotec.2010.09.845

[P-S.39]

Key Enzymes for the Optimization of CO2 Uptake and NitrogenConsumption in the C3 Photosynthetic Carbon Metabolism

A. Papini 1,∗, G. Nicosia 2, G. Stracquadanio 2, P. Liò 4, R. Umeton 3

1 Università di Firenze, Italy2 University of Catania, Italy3 Massachusetts Institute of Technology, United States4 University of Cambridge, United KingdomKeywords: Photosynthesis; CO2 uptake vs. Nitrogen; Pareto Opti-mality

In this research work have been identified the key enzymesto target in order to maximize CO2 uptake rate and minimize theprotein-nitrogen consumption. The aim is to re-arrange resourceallocation enzymes-wise in order to obtain a robust trade-offbetween CO2 uptake and the total amount of protein-nitrogen.The designed methodology, including multi-objective optimiza-tion, unravelled that Rubisco, Sedoheptulosebisphosphatase (SBPase),ADP-Glc pyrophosphorylase (ADPGPP) and Fru-1,6-bisphosphate(FBP) aldolase are the most influential enzymes in carbonmetabolism model (Fig. 1) where CO2 uptake maximization is con-cerned (our methodology raises this rate up to 36.149 �molm−2s−1;natural leaf value is 15.486 �molm−2s−1). Interesting insightsinclude the fact that the Rubisco enzyme participate with a very highconcentration; additionally, some of the photorespiratory enzymesthat should be almost switched off to reach the best configurationsknown (Zhu’07) cannot be effectively switched off because theyare involved in other processes carried by C3 plants. The pathway