Team:iBowu-China/Description
Project Descriptions
Glycerβ in a nutshell
Glycyrrhetinic Acid (GA) is an important herbal extract from the most widely used Chinese herbal medicine Licorice with applications both in the food and pharmaceutical industries. It is an approved effective medicine for peptic ulcers and has expectorant properties, and current research reported potential use for anti-viral, anti-bacterial, and in cancer treatments. The conventional extraction method using hydrolysis of glycyrrhizin (GL) suffers from high cost and high environmental pressure, which undermines its large-scale usage. Syn-bio pathways can potentially lower the cost, and are eco-friendly. Therefore, Team iBowu-China investigated synthetic methods using the enzyme beta-glucuronidase (bG) to hydrolyze GL into GA by experimenting with the coding sequence from different species. Our results indicate the enzyme can be stably produced with a good hydrolysis activity under proper conditions.
The heritage
Throughout the course of human civilization, herbs have played a vital role as traditional remedies to treat diseases. Stretching from the past to present, Prevalent tales of these herbs have emerged from the ancient Chinese stories of Shen Nong dating back to the herbal knowledge records in the Ebers Papyrus in 1550 BC Egypt, and to the magical herbs depicted in J.K Rowling’s Harry Potter. This baton is being passed in a relay race from one generation to the next, and now, with the help of synthetic biology, we can help carry it into the future.
Disadvantages of the traditional extraction methods
Many natural compounds derived from herbs were significant contributors to the curing of illness. Yet, these compounds face low production with traditional and chemical extraction methods with low efficiency and purity. Seeking solutions to this problem, we looked into using synthetic biology as an alternative method to yield higher production of useful herbal compounds.
Glycyrrhetinic Acid: essense in the Licorice
Specifically, we are targeting glycyrrhetinic acid, which is found in the Licorice root, a Chinese medicinal herb. Glycyrrhetinic acid is generated by hydrolyzing two glucuronide groups from glycyrrhizic acid. It is the main active pharmaceutical ingredient in licorice that has anti-inflammatory, immunity enhancement, anti-arrhythmia, anti-tumor, anti-virus, anti-cancer, and antitussive purposes. Therefore, glycyrrhetinic acid is a versatile substance widely used in food sweeteners, skincare products, and pectoral medicines such as Enoxodone. Furthermore, glycyrrhetinic acid is the main ingredient in clinical medicine to cure hepatitis, bronchitis, and AIDs.
Glycyrrhetinic Acid: great application value
Glycyrrhizic acid has great demand in Europe and North America. According to a report from Market Intelligence Data, the global market size for Glycyrrhetinic Acid will increase 15% in the next five years. However, the planting of licorice is not easy with high land occupation, selective seed sources. Because of the costly investment and low return, fewer growers are willing to plant licorice.
Glycyrrhetinic Acid: the problem in production
Furthermore, with the current direct extraction and chemical extraction methods, the yield of glycyrrhetinic acid remains low. This direct extraction method produces low glycyrrhetinic acid mass content of only 0.01% to 0.2%, resulting in low purity and yield. On the other hand, using acids to hydrolyze glycyrrhizic acid to Glycyrrhetinic acid can attain this high purity but has uncontrollable conditions and harsh reaction requirements of high temperature and pressure. What’s more, the use of acid-cracking reagents leads to severe environmental pollution and high production costs.
Our Solution
Therefore, our team is looking for a sustainable, efficient, and cost-effective method where we can have more control over the conditions for production. Since glycyrrhetinic acid is in lower concentrations compared to glycyrrhizic acid in licorice's root, we hope to generate glycyrrhetinic acid by hydrolyzing two glucuronide groups from glycyrrhizic acid with an enzyme β-glucuronidase. This protein encoded with the Gus gene on our artificially constructed plasmid will be amplified using E. coli dH5-alpha and expressed in E.coli bl21（DE3）when induced by IPTG. To increase the yield of β-glucuronidase for catalyzing glycyrrhetinic acid, we changed the T7 promoter on our plasmid to stronger ones that express more beta-glucuronidase using Gibson assembly.
References
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