In design, we have presented the 6 steps from which we conceived and studied our system. From these, the last one is the presented here: further insights on PLA production, considering what we have learnt from the issues investigated in Human Practices. Thus, the material presented here is the conclusive part of the project design, by which we give cohesion and perspectives to the work.
Objective: maximum optimization
During the report on legislation of banning plastics, we came out with the conclusion that price is a main constraint on changing to bioplastics and that, in consequence, efficiency in the production procedure was crucial.
Facing the question "What can we do with the results of our project to foster bioplastic consumption?", the answer turned out to be optimizing as much as we could the production system. On the modeling, we had already proposed mechanisms on the genetic level, so it was time to go a level further and design an optimal bioprocess system.
The immediat level after our molecular biology wet-lab, came up to be improving the fermentation conditions.
First, we decided to perform some experiments to maximize the growth conditions of P. putida. Given the Flux Balance Analysis results, we knew that using different substrates would vary the metabolism. We experimented with benzoic acid, glycerol and glucose. We did not have the time to check fructose and acid lactic, which would have been interesting.
As we did not manage to produce PLA, insights on scaling-up to the industrial level would not have provided realistic conclusions. In consequence, we focused on studying systems of optimization by using bioreactors and we designed a step-wised continuous system for the bioproduction of PLA. With it, we would expect the engineered Pseudomonas putida to dependent on less parameters than other systems, such as those using batch fermentation. We also took part of the Do-It-Yourself philosophy, and we manufactured some pieces of the bioprocess in a DIY manner, showing it can be affordable to implement.
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A whole-DIY-bioprocess for a metabolic engineered Pseudomonas putida KT2440 for bioproduction of Poly-(Lactic Acid).