5 Key Factors Affecting Fermentation Process

Biochemistry is the study of molecules (like proteins, carbohydrates, lipids, nucleic acids) and how they interact in the cells of living organisms.

Introduction to Biochemistry

Biochemistry is the study of molecules and the chemical reactions of life. It is the discipline that uses the principles and language of chemistry to explain biology at the molecular level. Biochemists have discovered that the chemical compounds and central metabolic processes are the same as those found in organisms as diverse as bacteria, plants, and humans. 

The basic principles of biochemistry are known to be common to all living organisms. Although in practice, scientists concentrate their research efforts on particular organisms, their results can be extrapolated to many other species.

🕰️ Brief History of Biochemistry

Year/Period	Historical Milestone
Ancient Times	Fermentation (e.g., wine and bread) was known and used.
1806	First enzyme (diastase) discovered by Anselme Payen.
1828	Friedrich Wöhler synthesized urea, showing that organic compounds could be made artificially.
1897	Eduard Buchner demonstrated fermentation in cell-free extracts – foundation of enzymology.
1926	James Sumner crystallized the enzyme urease, proving that enzymes are proteins.
1953	Watson & Crick described the double-helix structure of DNA.
2003	Human Genome Project completed, boosting molecular biochemistry.

Biochemistry is a Modern Science

Biochemistry emerged as a dynamic science only 100 years ago. However, the foundations for the field of work that led to the emergence of biochemistry as a modern science were laid many centuries earlier. The period before the 20th century witnessed rapid advances in the understanding of basic chemical principles such as reaction kinetics and the atomic composition of molecules. By the end of the 19th century, numerous chemicals produced by living organisms had been identified. Since then, biochemistry has become an organized discipline, and biochemists have elucidated many of the chemical processes of life. The growth of biochemistry and its influence on other disciplines will continue well into the 21st century.

In 1828, Friedrich Wöhler synthesized the organic compound urea by heating the inorganic compound ammonium cyanate.

This experiment showed for the first time that it was possible to synthesize compounds found exclusively in living organisms from common inorganic substances. It is now known that the synthesis and degradation of biological substances obey the same chemical and physical laws applicable to processes independent of biology. No special or "vitalist" processes are required to explain life at the molecular level. Many scientists trace the beginnings of biochemistry to Friedfrich Wöhler's synthesis of urea; however, it took another 75 years before the first biochemistry departments were established at universities. The two most important discoveries in the history of biochemistry are especially noteworthy: the discovery of the catalytic function of enzymes and the role of nucleic acids as information-carrying molecules. The large size of proteins and nucleic acids made their initial characterization difficult due to the techniques available in the first part of the 20th century. With the development of modern technology, we now have access to a wealth of information about how the structures of proteins and nucleic acids relate to their biological functions.

The first discovery—the identification of enzymes as catalysts for biological reactions—was partly a result of the research of Eduard Buchner. In 1897, Buchner demonstrated that cell-free yeast extracts could catalyze the fermentation of glucose into alcohol and carbon dioxide. Prior to this, scientists believed that only living cells could catalyze such complex biological reactions. The study of the nature of biological catalysts was investigated by Emil Fischer, a contemporary of Eduard Buchner. Fischer studied the catalytic effect of yeast enzymes in a simple reaction, the hydrolysis (breakdown by water) of sucrose (table sugar). Fischer proposed that during catalysis, an enzyme and its reactant, or substrate, combine to form an intermediate compound. He also proposed that only a molecule with a suitable structure could serve as a substrate for a given enzyme. Fischer described enzymes as rigid molds or locks, and substrates as their corresponding keys. 

Researchers soon understood that almost all of life's reactions were catalyzed by enzymes; thus, the modified lock-and-key theory of enzyme action remains the central tenet of modern biochemistry. Enzyme catalysis allows for very high yields with very few, if any, byproducts. In contrast, many catalyzed reactions in organic chemistry are considered acceptable if they achieve yields of 50 to 60%. Biochemical reactions must be efficient because byproducts can be toxic to cells, and their formation would waste precious energy. Of course, the other key property of enzyme catalysis is that biological reactions occur much more rapidly than without a catalyst.

The latter half of the 20th century witnessed tremendous advances in the area of ​​structural biology, particularly regarding protein structure. In the 1950s and 1960s, scientists at the University of Cambridge (UK), led by John C. Kendrew and Max Perutz, explained the first protein structures. Since then, the three-dimensional structures of more than 1,000 different proteins have been determined, and our understanding of complex protein biochemistry has increased significantly. 

These rapid advances were made possible by the availability of larger, faster computers and new software programs capable of performing the numerous calculations that were once customary to perform by hand or using simple calculators. Much of modern biochemistry depends on computers, leading to the creation of a new subdiscipline called bioinformatics.

Photograph 51, taken by Rosalind Franklin by "illuminating" DNA strands with X-rays.

The second major discovery in the history of biochemistry—the identification of nucleic acids as information molecules—occurred half a century after the experiments of Fischer and Buchner. In 1944, Oswald Avery, Colin MacLeod, and Maclyn McCarty extracted deoxyribonucleic acid (DNA) from a toxic strain of the bacterium Streptococcus pneumoniae and mixed it with a nontoxic strain of the same microorganism. As a result, the nontoxic strain was permanently transformed into a toxic strain. 

This experiment provided the first conclusive evidence that DNA is the genetic material. In 1953, James D. Watson and Francis H.C. Crick deduced the three-dimensional structure of DNA. The structure of DNA immediately suggested to Watson and Crick a method by which DNA could reproduce itself, or self-replicate, and thus transmit biological information to successive generations. Subsequent research showed that the information encoded in DNA was transcribed into ribonucleic acid (RNA) and then translated into protein.

The study of genetics in the context of nucleic acid molecules is part of molecular biology, and molecular biology is part of biochemistry.

James Watson and Francis Crick next to a cardboard and foil model of the DNA molecule.

As Crick predicted in 1958, the normal flow of information from nucleic acid to protein is irreversible. He referred to this one-way flow of information as the Central Dogma of molecular biology. The term "Central Dogma" is often misunderstood. Strictly speaking, it does not refer to the general flow of information referred to above, but to the fact that once information in nucleic acids is transferred to protein, it cannot flow back to nucleic acids.

🧪 Applications of Biochemistry

Field	Application
Medicine	Understanding disease mechanisms, drug design, clinical diagnostics.
Agriculture	Genetic engineering, crop improvement, pest-resistant plants.
Nutrition	Understanding nutrients, metabolism, dietary planning.
Pharmaceuticals	Drug discovery, vaccine development.
Forensic Science	DNA fingerprinting, toxicology.
Environmental Science	Bioremediation, pollution control using microbes.

🎯 Scope of Biochemistry

Biochemistry offers vast career and research opportunities in both academia and industry.

Sector	Opportunities
Academia & Research	Biochemical research, teaching, PhD/postdoc studies.
Healthcare	Clinical biochemist, diagnostics, pathology labs.
Biotech & Pharma	Drug development, quality control, product formulation.
Agriculture	Soil biochemistry, genetically modified crops.
Food Industry	Food safety, fermentation, quality assurance.
Cosmetics	Formulation of skin and hair products using biochemical principles.