BIOCHEMICAL TECHNOLOGIES: A BRIDGE BETWEEN BIOLOGY AND CHEMISTRY
Biochemistry is the study of the chemistry of living structures: a link between biology and chemistry aimed at understanding the complex chemical reactions that lie behind the origin of the cellular structure and the transformations of its components, such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules.
- The group of biochemical technologies includes technologies in the biochemical field , therefore the study of genetic material, as well as proteins and the biomolecules in cell structures. They can be classified on the basis of the object of study:
- - in the fields of molecular biology:
- nucleic acid technologies, focused on genetic engineering and the core of cell systems for the transformation and transfer of genes;
- polypeptide technologies, for studying the structure and function of proteins of a biological origin, and the synthesis of the same;
- biomolecules technologies, which are not the main object of genomics and proteomics, such as carbohydrates, lipids, and vitamins, etc., which constitute the remaining part of cellular metabolites and are studied in metabolomics;
- in systemic biology fields: cellular technologies, that do not concern the individual molecular mechanism but rather the dynamic interactions between the various molecules that lead, over time, to the creation of a system , as well as the interaction between cell systems to form tissues and organs.
Modern molecular technologies are rightly considered strategic if we are to meet the major challenge of the 21st century, i.e. long-term sustainable development. Actually, their vast potential in human health and primary production, as in many industrial processes, means new and more efficient technical applications which will be vital on an economic, environmental and even social scale.
NANOBIOTECHNOLOGIES: AN INTERDISCIPLINARY TECHNOLOGY
The concept of "nanotechnology" was developed in the 70’s in the field of macromolecular chemistry. The term was coined by Professor Norio Taniguchi in 1974: “Nanotechnology is generally considered the manipulation of substances, through the separation, consolidation and deformation, of an atom or molecule”. Therefore, it is a concept that has its roots in matter. In the 1980’s, the concept also came to include phenomenon and systems on a nanometric scale, therefore with a magnitude of around one thousandth of a metre. This happened at the same time as the discovery of Buckminsterfullerene, probably the first success in this new science, followed a few years later by the creation of carbon nanotubes. Today this technology is interdisciplinary and ranges from material physics to supramolecular chemistry, bioengineering and robotics, etc., with potential applications in computer technology (denser mass storage digital medium, for example), medicine ( "robots" programmed to remove special toxins, for example), biology (slowing or favouring the growth of tissues and/or micro-organisms, for example), etc. As macromolecular chemistry operates on the same order of magnitude, it was only natural to apply nanotechnology to biotechnology, which resulted in nanobiotechnologies. Nanobiotechnology uses nanotechnological concepts and instruments in the biological field or manipulates biological systems using nanotechnologies. Another application of nanobiotechnologies lies in the engineering of biological molecules for purposes that are completely different to those used in nature (e.g. nanotechnological "robots"). Vice versa, when biomolecules become part or support for nanotechnological systems, the term bionanotechnologies is preferred.
Fermentative processes can be considered the traditional biotechnologies "par excellence", as this class of natural process has been used since prehistoric times in the first forms of food technologies, such as bread and wine making. Not by chance, the term fermentation derives from the Latin fervere, in other words “to boil”, hailing to the effect observed in ancient times during wine making.
In biochemical terms, fermentation is an anaerobic process involving the catabolic demolition of carbohydrates, or organic compounds in general, by micro-organisms to produce energy.
Generally, in industrial microbiology, the word fermentation is used to describe any process that involves the culturing of a certain micro-organism, whether this is an aerobic, anaerobic or microaerophilic process. Recently, the term has also been used for the cell cultures of mammals and insects, and today "fermentation" tends to be used to define any bioprocess in which a fermenter is used.
A fermenter is a reactor (often called "bioreactor") designed specifically for the cultivation of micro-organisms (or cells), in a medium called culture medium. The main characteristic of a fermenter, with respect to any chemical reactor, is the capacity of the same to be sterilized and maintain this sterility, while its main function is to maintain a controlled environment suitable for the optimal growth of the micro-organism or cell, in order to obtain the desired product.
The dimensions of the fermenters vary considerably depending on the application and standard of production, going from the scale of one litre (generally glass) through to hundreds of litres (preferably steel, but sometimes also glass) or tens or hundreds of m3 (only steel). The smallest are generally used for laboratory studies or pilot tests.
Fermentative processes are widely used in all biotechnological fields, and the operative methods can be compared, irrespective of the scale of execution or application. These processes can be classified on the basis of the micro-organism (or cell) used in the process:
- - bacteria, the smallest of micro-organisms and the most widely used, generally require highly aerobic and, consequently very fast fermentations;
- - funguses, have longer fermentations, slightly aerobic or non-aerobic, and therefore require different processing methods;
- - moulds, generally sporogenous, grow well in anaerobic conditions, and are often used in the production of antibiotics;
- - yeasts, often prefer more oxygenated conditions, and are widely used in foodstuffs.
BIOCATALYSIS SPEED OF THE OTHER SUBSTANCES (REAGENTS)
A catalyst is a substance which, in a chemical reaction, acts reducing the energy required for the reaction to take place (in technical terms, it reduces the activation energy) and consequently increases the transformation speed of the other substances (reagents), remaining unchanged at the end of the process. Therefore a catalyst participates in a reaction, without being consumed or altered by the same reaction (at least until the denaturation processes takes place).
Biocatalytic processes are characterised by the use of biomolecules (enzymes and coenzymes) as catalysts in the relevant reactors called enzymators.
From a functional and methodological point of view, a biocatalytic process has many aspects in common with fermentation, with the big advantage that no sterile conditions are required. Therefore, an enzymator is much simpler than a fermenter, from a constructional point of view, and often simple cement tanks are used, which can be stirred but are kept in the open air.
Another strong point of this technology is the high level of selectivity of enzymes, which allows excellent control of the process in simple conditions, with low process costs and a reduced environmental impact (in traditional synthesis, the disposal of chemical catalysts is often a critical point for the whole process). For all these reasons, as well as for the extreme versatility, biocatalysis is becoming more and more popular in many sectors, such as the production of detergents, food technologies, tanning and textiles, the paper industry, fine chemistry and the production of biofuels.
PURIFICATION FROM FERMENTED BROTH TO THE PURE PRODUCT
At the end of the fermentative or biocatalytic process, a large volume of heterogeneous mix is obtained, called fermented broth, containing the desired product in solution with unwanted substances and the micro-organisms used. The purification process separates these substances in a controlled way, to obtain the desired product in the pure form, conform to the specifications defined by the market or regulations.
- The purification process can be classified on the basis of various criteria:
- - location of the relevant metabolite (intra or extra cellular);
- - concentration of the same in the final broth;
- - level of impurity and level of chemical-biological risk for the final broth;
- - chemical-physical characteristics and specifications of the desired product;
- - market price and intended use of the product.
- For this reason, there are various types of equipment for performing the fundamental operations involved in purification. A general process schedule envisages many of the following phases, if not all:
- - separation of the biomass from the liquid fraction;
- - extraction of the metabolite from the liquid fraction of the broth (alternatively, any cell lysis, in the case of intracellular metabolites );
- - concentration of the relevant fraction;
- - isolation of the product.
There are various purification techniques for each of the above phases, and the choice of these is conditioned by the process adopted, the required specifications of the product and sector of reference.
Synthesis is the execution of a chemical reaction or a sequence of consecutive chemical reactions to obtain one or more compounds. This sequence must be reproducible, reliable and, if used for industrial production, also scalable. The reactions in the sequence may be followed by physical processes involving separation (precipitation, distillation, extraction, etc.) to purify the products.
Many famous reactions in organic chemistry have dominated industrial production in the 20th century, in all sectors, from the production of basic reagents for industry, to the production of plastic polymers, to more refined pharmaceutical productions. Subsequently, the advent of biotechnological productions and fermentative processes in particular, changed the industrial world.
Today, chemical synthesis is being applied to biological molecules more and more often, with the aim of enhancing some characteristics (one example is the synthesis of acetylsalicylic acid, more commonly known as Aspirin). This is a case of semi-synthesis, a class of reactions that rightfully belongs to biotechnological productions and is becoming all the more important for industrial purposes, along with historical and consolidated synthetic processes which are still used mainly in the basic chemistry and petrochemical sector.
In fact, modern biotechnologies, which provide greater control of the biosynthetic processes in the cell, make it possible to perform most of the synthesis process with a given micro-organism, in controlled fermentative processes, so as to obtain the desired product with a few traditional synthesis stages.
FINISHING: GETTING PRODUCTS RESPECTING SPECIFICATIONS
The production of the active principle or the relevant metabolite is not the last item in the list of the possible technologies that can be used in biotechnological production.
The product must actually conform to applicable specifications, be they law or simply market specifications, in all of its phases, from the end of the production process to the fruition by the final user. This represents a fundamental necessity, especially in the pharmaceutical field and in pharmaceutical products for veterinary use, but also in food technologies, where biotechnological applications are being used to maintain the characteristics of primary productions (packing in a controlled atmosphere, for example).
This group therefore includes technologies that involve the physical transformation of the finished product, for example to enhance the homogeneity (micronization, encapsulation , etc.), or to simplify the use of the same (freeze-drying, dehydration, etc.).
Other technologies involve the control of any biological contaminants, (microfiltration, irradiation, etc.), and the sterilization of the finished product, for parenteral use for example.
In general, the preparation of ready-to-use products and the relevant packaging is a critical area of intervention in the pharmaceutical sector, that is also governed by strict regulations, but this is becoming more and more important also in the other biotechnological productive fields.