An interactive study of influential parameters for shikimic acid production using statistical approach, scale up and its inhibitory action on different lipases

Microbial engineering for shikimate biosynthesis

Shikimate, a precursor to the antiviral drug oseltamivir (Tamiflu®), can influence aromatic metabolites and finds extensive use in antimicrobial, antitumor, and cardiovascular applications. Consequently, various strategies have been developed for chemical synthesis and plant extraction to enhance shikimate biosynthesis, potentially impacting environmental conditions, economic sustainability, and separation and purification processes. Microbial engineering has been developed as an environmentally friendly approach for shikimate biosynthesis. In this review, we provide a comprehensive summary of microbial strategies for shikimate biosynthesis. These strategies primarily include chassis construction, biochemical optimization, pathway remodelling, and global regulation. Furthermore, we discuss future perspectives on shikimate biosynthesis and emphasize the importance of utilizing advanced metabolic engineering tools to regulate microbial networks for constructing robust microbial cell factories.

Shikimic acid biosynthesis in microorganisms: Current status and future direction

Shikimic acid (SA), a hydroaromatic natural product, is used as a chiral precursor for organic synthesis of oseltamivir (Tamiflu®, an antiviral drug). The process of microbial production of SA has recently undergone vigorous development. Particularly, the sustainable construction of recombinant Corynebacterium glutamicum (141.2 g/L) and Escherichia coli (87 g/L) laid a solid foundation for the microbial fermentation production of SA. However, its industrial application is restricted by limitations such as the lack of fermentation tests for industrial-scale and the requirement of growth-limiting factors, antibiotics, and inducers. Therefore, the development of SA biosensors and dynamic molecular switches, as well as genetic modification strategies and optimization of the fermentation process based on omics technology could improve the performance of SA-producing strains. In this review, recent advances in the development of SA-producing strains, including genetic modification strategies, metabolic pathway construction, and biosensor-assisted evolution, are discussed and critically reviewed. Finally, future challenges and perspectives for further reinforcing the development of robust SA-producing strains are predicted, providing theoretical guidance for the industrial production of SA.

Extraction of shikimic acid from water hyacinth (Eichhornia crassipes) using sonication: An approach towards waste valorization

Shikimic acid (SA) is a valuable compound found in water hyacinth and is a precursor for synthesis of antiviral drug oseltamivir phosphate (Tamiflu®) which is used to treat H5N1 avian influenza. In the present work, the acid was extracted from different morphological parts (stem, leaves, and roots) of water hyacinth (a notorious aquatic weed) using sonication. The parametric study has been conducted by varying sonication time (10-50 min), solvent composition (methanol + water), solvent volume (20-50 mL), amplitude of sonication (30-60%), and pulse ratio (20-50%) for improving the recovery of shikimic acid (SA), antioxidant activity (AA) and total phenolic content (TPC) of water hyacinth extract. Also, the acid was extracted conventionally as a benchmark study. The highest yield of 2.4% at 40 min and 3.1% at 30 min was observed in case of conventional and ultrasound assisted extraction (UAE), respectively for stem. Leaves showed a higher TPC value of 7.4 mg GAE/g biomass and a higher AA was observed 83.21% at 20 min for stem in case of conventional method. The highest TPC value of 11.11 mg GAE/g biomass has been observed for leaves while stem has shown the highest AA of 87.72% at 10 min of sonication time for UAE. It was possible to recover the valuable chemicals with better processing conditions in the case of UAE.

Uncovering Competitive and Restorative Effects of Macro- and Micronutrients on Sodium Benzoate Biodegradation

A model aromatic compound, sodium benzoate, is generally used for simulating aromatic pollutants present in textile effluents. Bioremediation of sodium benzoate was studied using the most abundant bacteria, Pseudomonas citronellolis, isolated from the effluent treatment plants of South Gujarat, India. Multiple nutrients constituting the effluent in actual conditions are proposed to have interactive effects on biodegradation which needs to be analyzed strategically for successful field application of developed bioremediation process. Two explicitly different sets of fractional factorial designs were used to investigate the interactive influence of alternative carbon, nitrogen sources, and inorganic micronutrients on sodium benzoate degradation. The process was negatively influenced by the co-existence of other carbon sources and higher concentration of KH₂PO₄ whereas NH₄Cl and MgSO₄ exhibited positive effects. Optimized concentrations of NH₄Cl, MgSO₄, and KH₂PO₄ were found to be 0.35, 1.056, and 0.3 mg L^–1 respectively by central composite designing. The negative effect of high amount of KH₂PO₄ could be ameliorated by increasing the amount of NH₄Cl in the biodegradation milieu indicating the possibility of restoration of the degradation capability for sodium benzoate degradation in the presence of higher phosphate concentration.

Production and Synthetic Modifications of Shikimic Acid

Shikimic acid is a natural product of industrial importance utilized as a precursor of the antiviral Tamiflu. It is nowadays produced in multihundred ton amounts from the extraction of star anise ( Illicium verum) or by fermentation processes. Apart from the production of Tamiflu, shikimic acid has gathered particular notoriety as its useful carbon backbone and inherent chirality provide extensive use as a versatile chiral precursor in organic synthesis. This review provides an overview of the main synthetic and microbial methods for production of shikimic acid and highlights selected methods for isolation from available plant sources. Furthermore, we have attempted to demonstrate the synthetic utility of shikimic acid by covering the most important synthetic modifications and related applications, namely, synthesis of Tamiflu and derivatives, synthetic manipulations of the main functional groups, and its use as biorenewable material and in total synthesis. Given its rich chemistry and availability, shikimic acid is undoubtedly a promising platform molecule for further exploration. Therefore, in the end, we outline some challenges and promising future directions.

Generation of aroE overexpression mutant of Bacillus megaterium for the production of shikimic acid

Background

Shikimic acid, the sole chemical building block for the antiviral drug oseltamivir (Tamiflu®), is one of the potent pharmaceutical intermediates with three chiral centers. Here we report a metabolically engineered recombinant Bacillus megaterium strain with aroE (shikimate dehydrogenase) overexpression for the production of shikimic acid.

Results

In a 7 L bioreactor, 4.2 g/L shikimic acid was obtained using the recombinant strain over 0.53 g/L with the wild type. The enhancement of total shikimate dehydrogenase activity was 2.13-fold higher than the wild type. Maximum yield of shikimic acid (12.54 g/L) was obtained with fructose as carbon source. It was isolated from the fermentation broth using amberlite IRA-400 resin and 89 % purity of the product was achieved.

Conclusion

This will add up a new organism in the armory for the fermentation based production which is better over plant based extraction and chemical synthesis of shikimic acid.

Electronic supplementary material

The online version of this article (doi:10.1186/s12934-015-0251-3) contains supplementary material, which is available to authorized users.