Nowadays, enzymes play an important role in many branches of industry. It is especially important to perfectly adapt fermentation processes to them in order to produce goods as efficiently as possible. This often requires very high temperatures. This was also the case with our chosen enzyme: the α-amylase. It deconstructs starches down into glucose and is present in the saliva of all life forms. Since the resulting sugar can be turned into alcohol, it can play an important role in the production of ethanol (bio-fuels). The optimum working condition for the amylase that is used in industrial contexts is between 82 and 86°C. In Austria, the largest ethanol plant alone produces 400,000t of starch rich fuel a year, which means that all the corn, wheat etc.
must be heated up to achieve these temperatures and kept there for hours at a time. If it were possible to create an amylase with a lower optimal working temperature, even if it were only by a few degrees, much in the way of CO2 emissions could be spared. If one takes even just the average levels of two plants processing starch, it would come to about 50 terajoules in energy savings a year, which is the equivalent of the yearly energy needs of 3,000 average Austrian households.
Synthetic biology, a new, growing branch of scientific
research, is making it possible to change the structures of enzymes. If one or more of thecanonical amino acids are exchanged for synthetic ones, proteins with totally new properties can be created. In order to get an organism to accept non-canonical amino acids into its metabolism, a reprogramming of its genetic code (the translation key for protein synthesis) is required.
The methods of the branch of synthetic biology were taught to the students of the HLFS Ursprung while working with scientists at the Max-Planck-Institute for Biochemistry in Martinsried on their project titled “Synthetic Biology Tested at School”. As part of this project, the students came upon the notion of producing a synthetic amylase. Dr. Nediljko Budisa gave a presentation at the HLFS Ursprung about his success in optimizing a lipase (an enzyme that plays a role in the metabolism of fat) with methods of synthetic biology. It is now able to achieve a lot more at lower temperatures, than has been normal for industrial contexts in the past.
We read in scientific papers written by the Japanese scientist Yoshida in 1958, that the harmless bacteria Bacillus subtilis can accept the non-canonical amino acid ethionine if its naturally occurring methonine, which is structurally very similar, is missing. Yoshida, however, had very different goals when he carried out his experiments. He wanted to better understand the details of protein synthesis, as the level of information that we had at the time was so much less than what is available today. But his experiment did make clear that Bacillus subtilis would be well suited for the production of a synthetic amylase.
And the students were able to actually create a functional amylase with the synthetics amino acid ethionine – and that is a
world-wide first - and norleucine on their own. Even the two scientists from the Max-Planck-Institute were amazed when they verified the results.
The students’ amylase 2.0 worked and deconstructed its natural equivalent starch very well. Pre-experiments show that it is more active, and therefore better than the natural example.
Further tests and examinations are still needed, however: What is its optimum temperature? Can it be autoclaved? Is it heat resistant? Does it “live” longer than the commercial amylase? And much more… This will continue to be analyzed at the Max-Planck-Institute. The innovative work done by the students at the HLFS Ursprung will be continued with new experiments and tests. The resulting publication will be a result of the equal cooperation of all its authors: students as well as professional scientists.
The young researchers showed that an enzyme’s blueprints can be targeted and changed and that enzyme evolution is even possible in the school laboratory.
What opportunities will open up?
Pimp my enzymes!