The Friendly Microbes: The Probiotics

Abrar Hussain

HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi-75270 Pakistan (abrarhussain0307@gmail.com)

Published by: https://sindhbiotech.com/magazine/ 

Microorganisms are only seen with a microscope, which means that their presence in or on the body and everywhere can visualized only by a microscope and identified and chartered by different microbiological assays. The coverage of all aspects of these microbes are studied under the branch of natural science, microbiology. Ordinarily when someone hears the term microbe or microorganism, unintentionally the negative aspects of microbes are circulating in their minds. But, in reality the scenario is different, which means that not all microorganisms are pathogenic and harmful, but these are used in a huge application, even for the betterment of human, and thus create the concept of biotechnology, in which the microorganisms are used for the help of humanity. Think about the human microbiota (the collection of all microbes in or on the human body) which is 10 times more than the human body’s cells, and can add up to 2kg of weight and 60,000 genes. If all these microbes were supposed to be dangerous, what would have happened to humans? This thinking and the exclusive presence of microbes in the gut, give an idea that not all these microbes are dangerous, a large number of them are known as friendly or beneficial microbes, scientifically with certain characteristics, and are known as probiotics.  

The concept of probiotics was developed by a Nobel Laureate, Elie Metchnikoff in the early 20^th century, for those microorganisms which have the ability to enhance the host’s life span. With time the term was defined by different scientists, WHO/FAO, and finally by the International Scientific Association of Probiotics and Prebiotics (ISAPP). Probiotics are live microorganisms that when administered in adequate amounts can confer health benefit to a host. The probiotic science is growing rapidly which is shown by number of publications targeting the various features of probiotics. Although there are selection criteria that must be followed by a strain (probiotics is strain-dependent phenomena), but still their number is still increasing rapidly. Currently, seven genera of microorganisms are proposed for their probiotic potential. The most common genera are Lactobacillus and Bifidobacterium followed by Enterococcus. The genus Enterococcus has special properties like genome plasticity, and enterocins production (anti-bacterial substance), which make them fit in the probiotic category, as this genus is not included in Generally Recognized As Safe (GRAS) status.

Which microorganisms are used as probiotics? There is guidelines proposed by European Food Safety Agency (EFSA), Food and Agriculture Organization (FAO), and World Health Organization (WHO), which must be properly stated by the probiotic developer and manufacturer. The strain safety i.e. no virulence and antibiotic resistance genes etc. must be ensured, and the technical and biotechnological properties must be validated. The desired properties in probiotic microorganisms include tolerance to harsh conditions (gut and biotechnological process), free from virulence traits, no antibiotic-resistance genes, production of antimicrobial substances (bacteriocins), killing pathogens, adherence to the mucosal cells, and competition for binding in the gut. There are some properties of selection that are changing with specific applications and usage. The probiotic strain that are developed for human usage require more specific and safety evaluation. The different form of probiotics is also tested for their long-term storage and safety.

Why probiotics got high attention in the research community? The probiotics have a high number of health benefits that range from gut restoration potential to treatment of disease, and from biotechnological applications to food safety enhancement. As already stated these are friendly microorganisms which have an impact on their host, like they can enhance the immunity of the host, restore the gut dysbiosis (imbalance in the gut microbiota), exclude the enteric pathogens, produce bacteriocins, and secrete some metabolites. The more health benefits that are associated with probiotics are, the treatment of diseases, particularly digestive disorders, have anti-aging potential (Gerobiotics), effect on the psychological functions of the brain and mind (Psychobiotics), produce short-chain fatty acids, nitrous oxides, etc., eradicate the food-borne pathogens, enhance the food shelf life, give taste and aroma to the products, maintain the gut integrity, reduce stress and anxiety, helpful in the allergy treatment, and can boost the mood of an individual. Probiotics can also have a safe usage in pregnancy, and can enhance the testosterone level and sperm quality in males. Similarly, in aged people, the lose of memory and blurred vision like problems can also vanish with probiotics as they can help in the focus memory. Currently, extensive research is ongoing to enhance the existing potential of probiotic strains. Probiotics are also considered multifarious weapons for disease treatment and biotechnological applications.

How probiotics are transferred to the host and what are the different forms of probiotics? The probiotics are transferred to the host by various vehicles like yogurt, desserts, cheese, and juices. Each vehicle has its pros and cons, but commonly fermented milk and yogurt are used as delivery vehicles. The common forms of probiotics are tablets, capsules, powders, and liquids. Different form has both advantages and limitations like capsular form required no binder but ineffective in the upper GI tract. Similarly, the tablet form has the advantage of easy administration and effectiveness in the upper GT tract but require binders and has high cost.

How probiotics perform its action? When the probiotics enter to host by various means, they can perform their action through different mechanism. However, the general mechanism of action includes the enhancement of the epithelial cells barrier, promotion binding to mucosal cells, exclusion the enteric pathogens, production of bacteriocins, and immunomodulatory effects. Their action is mostly based on the expression of a particular molecule or secretion of different metabolites, while its effectiveness their related to their adherence and colonization potential.

How much probiotics are effective, or what is the dosage of effective probiotics? Being a strain-dependent nature the amount may vary with strains. Generally, 10⁷ to 10⁹ CFU/ml is recommended for effective usage. The probiotic product should be properly labeled like genus, species, strain, and identification number. Every year the probiotic concerned organization receives a large number of application, calming the potential of their identified probiotics but very less number are approved for animal and human usage, or as a food supplement.

What are the current trends in probiotics? Modern day technologies are opening new doors for applications. In probiotics, the concept of engineered probiotics got the attention. In this approach, the existing strains are edited with the desired properties. The extensive usage of the CRISPR-Cas (clustered regularly interspaced short palindromic repeats) system in different applications is also applied in probiotics and hence, gives the birth of the CRISPR-biotcs. The attraction of the field is also fruitful as a large number of industries are taking an interest in the development of probiotic products. It is estimated that the total incremental growth in probiotics will be $ 31.28 billion from 2019-2024. This huge industry is now developed very well and can contribute to society.

In conclusion, the concept of friendly bacteria is applied practically and used in different applications like food, pharmaceuticals, industrial, biotechnological, and disease treatment. By definition, probiotics are live microorganisms which when taken in enough amounts confer the health benefit on the host. Probiotics have a pretty known beneficial effect and helping in various ways. The development of probiotics can change our idea about the negative affiliation of microbes when we talk about microorganisms. Recently, the field is growing fast and new ideas and concepts are developing with advanced functionalities.

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