Deciphering metabolic responses of biosurfactant lichenysin on biosynthesis of poly-γ-glutamic acid
- 74 Downloads
Poly-γ-glutamic acid (γ-PGA) is an extracellularly produced biodegradable polymer, which has been widely used as agricultural fertilizer, mineral fortifier, cosmetic moisturizer, and drug carrier. This study firstly discovered that lichenysin, as a biosurfactant, showed the capability to enhance γ-PGA production in Bacillus licheniformis. The exogenous addition of lichenysin improved the γ-PGA yield up to 17.9% and 21.9%, respectively, in the native strain B. licheniformis WX-02 and the lichenysin-deficient strain B. licheniformis WX02-ΔlchAC. The capability of intracellular biosynthesis of lichenysin was positively correlated with γ-PGA production. The yield of γ-PGA increased by 25.1% in the lichenysin-enhanced strain B. licheniformis WX02-Psrflch and decreased by 12.2% in the lichenysin-deficient strain WX02-ΔlchAC. Analysis of key enzyme activities and gene expression in the TCA cycle, precursor glutamate synthesis, and γ-PGA synthesis pathway revealed that the existence of lichenysin led to increased γ-PGA via shifting the carbon flux in the TCA cycle towards glutamate and γ-PGA biosynthetic pathways, minimizing by-product formation, and facilitating the uptake of extracellular substrates and the polymerization of glutamate to γ-PGA. Insight into the mechanisms of enhanced production of γ-PGA by lichenysin would define the essential parameters involved in γ-PGA biosynthesis and provide the basis for large-scale production of γ-PGA.
KeywordsPoly-γ-glutamic acid Lichenysin Bacillus licheniformis Glutamate biosynthetic pathway γ-PGA biosynthetic pathway
Funding for this project has been provided by the National Natural Science Foundation of China (Grant No: 31500074), the National Program on Key Basic Research Project (973 Program, No. 2015CB150505), and the Technical Innovation Special Fund of Hubei Province (No. 2018ACA149). The funding body had no role in the design of the study, nor in the collection, analysis, or interpretation of data.
Compliance with ethical standards
The authors declare that they have no competing interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
Consent to participate
Consent for publication
- Ben-Zur N, Goldman DM (2007) γ-Poly glutamic acid: a novel peptide for skin care. Cosmet Toilet Mag 122:64–72Google Scholar
- Cromwick AM, Birrer GA, Gross RA (1996) Effects of pH and aeration on gamma-poly (glutamic acid) formation by Bacillus licheniformis in controlled batch fermentor cultures. Biotechnol Bioeng 50(2):222–227Google Scholar
- Ertan H (1992) Some properties of glutamate dehydrogenase, glutamine synthetase and glutamate synthase from Corynebacterium callunae. Arch Microbiol 158(1):35–41Google Scholar
- Kada S, Nanamiya H, Kawamura F, Horinouchi S (2004) Glr, a glutamate racemase, supplies d-glutamate to both peptidoglycan synthesis and poly-γ-glutamate production in γ-PGA-producing Bacillus subtilis. FEMS Microbiol Lett 236(1):13–20. https://doi.org/10.1111/j.1574-6968.2004.tb09621.x Google Scholar
- Kimura K, Fujimoto Z (2010) Enzymatic degradation of poly-gamma-glutamic acid. In: Hamano Y (ed) Amino-acid Homopolymers occurring in nature. Microbiology monographs, vol 15. Springer, BerlinGoogle Scholar
- Kubota H, Nambu Y, Endo T (1993) Convenient and quantitative esterification of poly(γ-glutamic acid) produced by microorganism. J Polym Sci A Polym Chem 31(11):2877–2878Google Scholar
- Sekine T, Nakamura T, Shimizu Y, Ueda H, Matsumoto K, Takimoto Y, Kiyotani T (2001) A new type of surgical adhesive made from porcine collagen and polyglutamic acid. J Biomed Mater Res A 54(2):305–310Google Scholar
- Shimizu H, Tanaka H, Nakato A, Nagahisa K, Kimura E, Shioya S (2003) Effects of the changes in enzyme activities on metabolic flux redistribution around the 2-oxoglutarate branch in glutamate production by Corynebacterium glutamicum. Bioprocess Biosyst Eng 25(5):291–298Google Scholar
- Shirai T, Nakato A, Izutani N, Nagahisa K, Shioya S, Kimura E, Kawarabayasi Y, Yamagishi A, Gojobori T, Shimizu H (2005) Comparative study of flux redistribution of metabolic pathway in glutamate production by two coryneform bacteria. Metab Eng 7(2):59–69. https://doi.org/10.1016/j.ymben.2004.10.001 Google Scholar
- Sonoda C, Sakai K, Murase K (2000) Bitterness relieving agent. International Patent Application: Publication No. WO2000/021390Google Scholar
- Tian G, Wang Q, Wei X, Ma X, Chen S (2017) Glutamate dehydrogenase (RocG) in Bacillus licheniformis WX-02: enzymatic properties and specific functions in glutamic acid synthesis for poly-γ-glutamic acid production. Enzym Microb Technol 99:9–15. https://doi.org/10.1016/j.enzmictec.2017.01.002 Google Scholar
- Wang Q, Chen S, Zhang J, Sun M, Liu Z, Yu Z (2008) Co-producing lipopeptides and poly-γ-glutamic acid by solid-state fermentation of Bacillus subtilis using soybean and sweet potato residues and its biocontrol and fertilizer synergistic effects. Bioresour Technol 99(8):3318–3323. https://doi.org/10.1016/j.biortech.2007.05.052 Google Scholar
- Wu Q, Xu H, Shi N, Yao J, Li S, Ouyang P (2008) Improvement of poly(γ-glutamic acid) biosynthesis and redistribution of metabolic flux with the presence of different additives in Bacillus subtilis CGMCC 0833. Appl Microbiol Biotechnol 79(4):527–535. https://doi.org/10.1007/s00253-008-1462-x Google Scholar
- Xiong H, Wei X, Ji Z, Sun M, Chen S (2008) Expression of Vitreoscilla hemoglobin in poly g-glutamic acid-producing Bacillus licheniformis WX-02. Microbiol China 35:1703–1707Google Scholar
- Ye HF (2006) Poly (gamma, l-glutamic acid)-cisplatin conjugate effectively inhibits human breast tumor xenografted in nude mice. Biomaterials 27:5958–5965. https://doi.org/10.1016/j.biomaterials.2006.08.016 Google Scholar