Amylases are enzymes that lie at the center of various industrial processes, from food production to biofuel development. Their strong ability to convert starch into simple sugars makes them irreplaceable in brewing, baking, and even detergent manufacturing.
What is Amylase, and Why Is It Important?
Amylase is an enzyme that degrades starch into dextrin and shorter polymers of glucose molecules. This enzyme is produced by plants, animals, and microorganisms. Alpha amylase, beta amylase, and gamma amylase are three different types of microbial amylases. All of them have their own specific ways of functioning. The application is extremely broad and encompasses bread making and the production of ethanol for biofuels. However, even though both plants and animals produce amylase, at industrial scales, this production has to rely primarily on microorganisms due to efficiency, adaptability, and scale-up potential.
Amylase production by fermentation is affected by nutritional factors such as nitrogenous and carbon sources, metal ions, and physicochemical factors like pH, inoculum age, inoculum concentration, agitation, incubation temperature, and incubation time.
Types of Amylases
Alpha Amylase
Alpha amylases are calcium metalloenzymes, completely unable to function in the absence of calcium. In human physiology, both the salivary and pancreatic amylases are alpha amylases, also found in plants, fungi, and bacteria.
Beta Amylase
Beta amylase is another form of amylase synthesized by bacteria, fungi, and plants. During the ripening of fruit, beta amylase breaks starch into maltose, resulting in the sweet flavor of ripe fruit. Both alpha and beta amylase are present in seeds; beta amylase is present in an inactive form prior to germination, whereas alpha amylase and proteases appear once germination has begun. Animal tissues do not contain beta amylase.
Gamma Amylase
Gamma amylase, also known as glucoamylase, catalyzes the hydrolysis of α-1,4 and α-1,6 glycosidic bonds. Compared to other types of amylase, gamma amylase is the most effective enzyme in acidic environments.
Microbial Sources: The Heroes Behind Amylase Production
Microorganisms serve as the leading source of amylase production. Their easy reproduction and good response to well-defined conditions make them a good choice for massive enzyme synthesis.
Bacteria
Bacillus species, such as Bacillus subtilis and Bacillus licheniformis, are perfect producers of thermostable amylase, useful for high-temperature processes in industrial plants.
Thermophilic bacteria like Geobacillus stearothermophilus are excellent representatives for extreme heat conditions, making them suitable for specific industrial applications.
Fungi
The two most popular fungal sources used are Aspergillus niger and Aspergillus oryzae, which are known for secreting enormous quantities of amylase extracellularly. Other species from the genus Penicillium have also been found useful due to their specific enzymatic properties.
Actinomycetes
Filamentous bacteria from the Streptomyces genus generate amylase that functions across a wide range of pH and temperature conditions.
Yeasts
Although used less frequently, some yeast species, such as Saccharomyces cerevisiae, can synthesize amylase, albeit in lower quantities than bacteria and fungi.
Fermentation Techniques: How Amylase Is Made
The basis of amylase production is fermentation. Some common methods include:
Submerged Fermentation (SmF)
In this method, microorganisms are grown in a liquid nutrient medium under controlled conditions.
- Advantages: High enzyme yield, easy control of temperature, pH, and oxygen levels.
- Application: Ideal for large-scale production of bacterial and fungal amylases.
Solid-State Fermentation (SSF)
Microorganisms are grown on solid substrates such as wheat bran or rice bran, with minimal free water.
- Advantages: Economical, utilizes agricultural waste, and produces highly concentrated amylase.
- Application: Often used for the production of fungal amylase.
Semi-Solid Fermentation (SSF)
A hybrid of SmF and SSF, combining the benefits of both methods for improved enzyme yield and lower production costs.
Optimizing Amylase Production
To ensure efficiency in the production process, several factors should be fine-tuned:
- Strain Selection: High-yielding microbial strains can be of natural or genetic origin.
- Culture Conditions: Maintaining optimal temperature (30-60°C), pH (5.0-9.0), and oxygen levels.
- Nutrients: Supplying proper carbon (starch, glucose) and nitrogen (peptone, yeast extract) sources.
- Inducers: The addition of maltose or dextrin can stimulate amylase production.
Applications of Amylase in Industry
- Food and Beverages: Improves bread texture and shelf life in baking and converts starch into fermentable sugars in brewing.
- Biofuels: Starch breakdown in crops is necessary for bioethanol production.
- Textiles and Paper: Removes starch-based sizing in textiles and modifies coatings in paper manufacturing.
- Detergents: Breaks down starch-based stains in laundry for more efficient cleaning.
The Future of Amylase Production
Biotechnology is continuously evolving, opening new horizons for amylase production.
- Genetic Engineering: Development of strains with higher yield and greater stability under extreme conditions.
- Sustainability: Utilizing agricultural residues such as rice bran or potato peels as low-cost substrates.
- Immobilization Technology: Designing reusable amylase systems for continuous industrial processes.
Conclusion
Amylase production has opened a world of possibilities for several industries by providing a sustainable and efficient means to meet increasing demand. With continuous advancements in strain development and fermentation technology, the future of amylase production looks brighter than ever.
References
- William B. Salt II, Schenker S. Amylase—Its Clinical Significance: A Review of the Literature. Medicine. 1976 Jul 1;55(4):269-89.
- Joshin, Andhare P, Marchawala F, Bhattacharya I, and Upadhyay D. A Study on Amylase: Review. International Journal of Biology, Pharmacy, and Allied Science (IJBPAS). 2021 April 10(4):333-340.
- Kaushal J, Singh G, Arya SK. Emerging Trends and Future Prospects in Enzyme Technology. Value-Addition in Food Products and Processing through Enzyme Technology. 2022 Jan 1:491-503.
- Singh SU, Sharma VI, Soni ML, Das SH. Biotechnological Applications of Industrially Important Amylase Enzyme. International Journal of Pharma and Bio Sciences. 2011;2(1):486-96.
Authors
Mr. Anshu Gupta & Dr. Latika P. Shendre*
Dr. D. Y. Patil Biotechnology and Bioinformatics Institute,
Dr. D. Y. Patil Vidyapeeth, Tathawade, Pune - 411033, Maharashtra, India.
Email: latika.shendre@dpu.edu.in