Improvement of macrolactins production by the genetic adaptation of Bacillus siamensis A72 to saline stress via adaptive laboratory evolution

Abstract Background Macrolactins, a type of macrolide antibiotic, are toxic to the producer strains. As such, its level is usually maintained below the lethal concentration during the fermentation process. To improve the production of macrolactins, we applied adaptive laboratory evolution technology...

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Main Authors: Yuman Gan, Meng Bai, Xiao Lin, Kai Liu, Bingyao Huang, Xiaodong Jiang, Yonghong Liu, Chenghai Gao
Format: Article
Language:English
Published: BMC 2022-07-01
Series:Microbial Cell Factories
Subjects:
Online Access:https://doi.org/10.1186/s12934-022-01871-9
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author Yuman Gan
Meng Bai
Xiao Lin
Kai Liu
Bingyao Huang
Xiaodong Jiang
Yonghong Liu
Chenghai Gao
author_facet Yuman Gan
Meng Bai
Xiao Lin
Kai Liu
Bingyao Huang
Xiaodong Jiang
Yonghong Liu
Chenghai Gao
author_sort Yuman Gan
collection DOAJ
description Abstract Background Macrolactins, a type of macrolide antibiotic, are toxic to the producer strains. As such, its level is usually maintained below the lethal concentration during the fermentation process. To improve the production of macrolactins, we applied adaptive laboratory evolution technology to engineer a saline-resistant mutant strain. The hypothesis that strains with saline resistance show improved macrolactins production was investigated. Results Using saline stress as a selective pressure, we engineered a mutant strain with saline resistance coupled with enhanced macrolactins production within 60 days using a self-made device. As compared with the parental strain, the evolved strain produced macrolactins with 11.93% improvement in non-saline stress fermentation medium containing 50 g/L glucose, when the glucose concentration increased to 70 g/L, the evolved strain produced macrolactins with 71.04% improvement. RNA sequencing and metabolomics results revealed that amino acid metabolism was involved in the production of macrolactins in the evolved strain. Furthermore, genome sequencing of the evolved strain revealed a candidate mutation, hisD D41Y, that was causal for the improved MLNs production, it was 3.42 times higher than the control in the overexpression hisD D41Y strain. Results revealed that saline resistance protected the producer strain from feedback inhibition of end-product (macrolide antibiotic), resulting in enhanced MLNs production. Conclusions In the present work, we successfully engineered a mutant strain with enhanced macrolactins production by adaptive laboratory evolution using saline stress as a selective pressure. Based on physiological, transcriptomic and genetic analysis, amino acid metabolism was found to benefit macrolactins production improvement. Our strategy might be applicable to improve the production of other kinds of macrolide antibiotics and other toxic compounds. The identification of the hisD mutation will allow for the deduction of metabolic engineering strategies in future research.
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spelling doaj.art-69e8729a2b364e328fc08196252d47a12022-12-22T03:04:47ZengBMCMicrobial Cell Factories1475-28592022-07-0121111510.1186/s12934-022-01871-9Improvement of macrolactins production by the genetic adaptation of Bacillus siamensis A72 to saline stress via adaptive laboratory evolutionYuman Gan0Meng Bai1Xiao Lin2Kai Liu3Bingyao Huang4Xiaodong Jiang5Yonghong Liu6Chenghai Gao7Institute of Marine Drugs, Guangxi University of Chinese MedicineInstitute of Marine Drugs, Guangxi University of Chinese MedicineInstitute of Marine Drugs, Guangxi University of Chinese MedicineInstitute of Marine Drugs, Guangxi University of Chinese MedicineInstitute of Marine Drugs, Guangxi University of Chinese MedicineInstitute of Marine Drugs, Guangxi University of Chinese MedicineInstitute of Marine Drugs, Guangxi University of Chinese MedicineInstitute of Marine Drugs, Guangxi University of Chinese MedicineAbstract Background Macrolactins, a type of macrolide antibiotic, are toxic to the producer strains. As such, its level is usually maintained below the lethal concentration during the fermentation process. To improve the production of macrolactins, we applied adaptive laboratory evolution technology to engineer a saline-resistant mutant strain. The hypothesis that strains with saline resistance show improved macrolactins production was investigated. Results Using saline stress as a selective pressure, we engineered a mutant strain with saline resistance coupled with enhanced macrolactins production within 60 days using a self-made device. As compared with the parental strain, the evolved strain produced macrolactins with 11.93% improvement in non-saline stress fermentation medium containing 50 g/L glucose, when the glucose concentration increased to 70 g/L, the evolved strain produced macrolactins with 71.04% improvement. RNA sequencing and metabolomics results revealed that amino acid metabolism was involved in the production of macrolactins in the evolved strain. Furthermore, genome sequencing of the evolved strain revealed a candidate mutation, hisD D41Y, that was causal for the improved MLNs production, it was 3.42 times higher than the control in the overexpression hisD D41Y strain. Results revealed that saline resistance protected the producer strain from feedback inhibition of end-product (macrolide antibiotic), resulting in enhanced MLNs production. Conclusions In the present work, we successfully engineered a mutant strain with enhanced macrolactins production by adaptive laboratory evolution using saline stress as a selective pressure. Based on physiological, transcriptomic and genetic analysis, amino acid metabolism was found to benefit macrolactins production improvement. Our strategy might be applicable to improve the production of other kinds of macrolide antibiotics and other toxic compounds. The identification of the hisD mutation will allow for the deduction of metabolic engineering strategies in future research.https://doi.org/10.1186/s12934-022-01871-9MacrolactinsAdaptive laboratory evolutionSaline toleranceAmino acid metabolismFeedback inhibition
spellingShingle Yuman Gan
Meng Bai
Xiao Lin
Kai Liu
Bingyao Huang
Xiaodong Jiang
Yonghong Liu
Chenghai Gao
Improvement of macrolactins production by the genetic adaptation of Bacillus siamensis A72 to saline stress via adaptive laboratory evolution
Microbial Cell Factories
Macrolactins
Adaptive laboratory evolution
Saline tolerance
Amino acid metabolism
Feedback inhibition
title Improvement of macrolactins production by the genetic adaptation of Bacillus siamensis A72 to saline stress via adaptive laboratory evolution
title_full Improvement of macrolactins production by the genetic adaptation of Bacillus siamensis A72 to saline stress via adaptive laboratory evolution
title_fullStr Improvement of macrolactins production by the genetic adaptation of Bacillus siamensis A72 to saline stress via adaptive laboratory evolution
title_full_unstemmed Improvement of macrolactins production by the genetic adaptation of Bacillus siamensis A72 to saline stress via adaptive laboratory evolution
title_short Improvement of macrolactins production by the genetic adaptation of Bacillus siamensis A72 to saline stress via adaptive laboratory evolution
title_sort improvement of macrolactins production by the genetic adaptation of bacillus siamensis a72 to saline stress via adaptive laboratory evolution
topic Macrolactins
Adaptive laboratory evolution
Saline tolerance
Amino acid metabolism
Feedback inhibition
url https://doi.org/10.1186/s12934-022-01871-9
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