Author:
Wang Lingya,Wang Anran,Wang Dongmei,Hong Jiong
Abstract
Abstract
Background
Glucose repression in yeast leads to the sequential or diauxic utilization of mixed sugars and reduces the co-utilization of glucose and xylose from lignocellulosic biomasses. Study of the glucose sensing pathway helps to construct glucose repression-released yeast strains and enhance the utilization of lignocellulosic biomasses.
Results
Herein, the glucose sensor/receptor repressor (SRR) pathway of Kluyveromyces marxianus which mainly consisted of KmSnf3, KmGrr1, KmMth1, and KmRgt1 was studied. The disruption of KmSNF3 led to a release of glucose repression, enhanced xylose consumption and did not result in deficient glucose utilization. Over-expression of glucose transporter gene restored the mild decrease of glucose utilization ability of Kmsnf3 strain to a similar level of the wildtype strain but did not restore glucose repression. Therefore, the repression on glucose transporter is parallel to glucose repression to xylose and other alternative carbon utilization. KmGRR1 disruption also released glucose repression and kept glucose utilization ability, although its xylose utilization ability was very weak with xylose as sole carbon source. The stable mutant of KmMth1-ΔT enabled the release of glucose repression irrespective that the genetic background was Kmsnf3, Kmmth1, or wildtype. Disruption of KmSNF1 in the Kmsnf3 strain or KmMTH1-ΔT overexpression in Kmsnf1 strain kept constitutive glucose repression, indicating that KmSNF1 was necessary to release the glucose repression in both SRR and Mig1-Hxk2 pathway. Finally, overexpression of KmMTH1-ΔT released the glucose repression to xylose utilization in S. cerevisiae.
Conclusion
The glucose repression-released K. marxianus strains constructed via a modified glucose SRR pathway did not lead to a deficiency in the utilization ability of sugar. The obtained thermotolerant, glucose repression-released, and xylose utilization-enhanced strains are good platforms for the construction of efficient lignocellulosic biomass utilization yeast strains.
Funder
National Natural Science Foundation of China
Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project
National Key Research and Development Program of China
Publisher
Springer Science and Business Media LLC
Subject
Applied Microbiology and Biotechnology,Bioengineering,Biotechnology
Reference42 articles.
1. Krstic M, Maksimovic Z, Ibric S, Bakic T, Prodanovic J, Razic S. Lignocellulosic biomass as a source of microcrystalline cellulose - chemical and technological characterization and future perspectives. Cell Chem Technol. 2018;52:577–88. https://doi.org/.
2. Saha BC. Hemicellulose bioconversion. J Ind Microbiol Biotechnol. 2003;30:279–91. https://doi.org/10.1007/s10295-003-0049-x.
3. Stasyk OG, Stasyk OV. Glucose Sensing and Regulation in Yeasts. In Sibirny, A, editor, Non-conventional Yeasts: from Basic Research to Application.Switzerland: Springer Cham,2019, pp. 477–519.https://doi.org/10.1007/978-3-030-21110-3.
4. Steyfkens F, Zhang ZQ, Van Zeebroeck G, Thevelein JM. Multiple transceptors for macro- and micro-nutrients control diverse cellular properties through the PKA pathway in yeast: a paradigm for the rapidly expanding world of eukaryotic nutrient transceptors up to those in human cells. Front Pharmacol. 2018;9:191. https://doi.org/10.3389/fphar.2018.00191.
5. Barrett L, Orlova M, Maziarz M, Kuchin S. Protein kinase a contributes to the negative control of Snf1 protein kinase in Saccharomyces cerevisiae. Eukaryot Cell. 2012;11:119–28. https://doi.org/10.1128/Ec.05061-11.