Adaptive Enrichment of a Thermophilic Bacterial Isolate for Enhanced Enzymatic Activity

The mimicking of evolution on a laboratory timescale to enhance biocatalyst specificity, substrate utilization activity, and/or product formation, is an effective and well-established approach that does not involve genetic engineering or regulatory details of the microorganism. The present work empl...

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Main Authors: Tanvi Govil, Priya Saxena, Dipayan Samanta, Sindhu Suresh Singh, Sudhir Kumar, David R. Salem, Rajesh K. Sani
Format: Article
Language:English
Published: MDPI AG 2020-06-01
Series:Microorganisms
Subjects:
Online Access:https://www.mdpi.com/2076-2607/8/6/871
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spelling doaj-6a0a09207aef4c9fb2a2e69c0b9cf1b52020-11-25T02:51:30ZengMDPI AGMicroorganisms2076-26072020-06-01887187110.3390/microorganisms8060871Adaptive Enrichment of a Thermophilic Bacterial Isolate for Enhanced Enzymatic ActivityTanvi Govil0Priya Saxena1Dipayan Samanta2Sindhu Suresh Singh3Sudhir Kumar4David R. Salem5Rajesh K. Sani6Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USADepartment of Biotechnology & Bioinformatics, Jaypee University of Information Technology, Solan, Himachal Pradesh 173215, IndiaDepartment of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USADepartment of Nanoscience and Nanoengineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USADepartment of Biotechnology & Bioinformatics, Jaypee University of Information Technology, Solan, Himachal Pradesh 173215, IndiaDepartment of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USADepartment of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USAThe mimicking of evolution on a laboratory timescale to enhance biocatalyst specificity, substrate utilization activity, and/or product formation, is an effective and well-established approach that does not involve genetic engineering or regulatory details of the microorganism. The present work employed an evolutionary adaptive approach to improve the lignocellulose deconstruction capabilities of the strain by inducing the expression of laccase, a multicopper oxidase, in <i>Geobacillus</i> sp. strain WSUCF1. This bacterium is highly efficient in depolymerizing unprocessed lignocellulose, needing no preprocessing/pretreatment of the biomasses. However, it natively produces low levels of laccase. After 15 rounds of serially adapting this thermophilic strain in the presence of unprocessed corn stover as the selective pressure, we recorded a 20-fold increase in catalytic laccase activity, at 9.23 ± 0.6 U/mL, in an adapted yet stable strain of <i>Geobacillus</i> sp. WSUCF1, compared with the initial laccase production (0.46 ± 0.04 U/mL) obtained with the unadapted strain grown on unprocessed corn stover before optimization. Chemical composition analysis demonstrated that lignin removal by the adapted strain was 22 wt.% compared with 6 wt.% removal by the unadapted strain. These results signify a favorable prospect for fast, cost competitive bulk production of this thermostable enzyme. Also, this work has practical importance, as this fast adaptation of the <i>Geobacillus</i> sp. strain WSUCF1 suggests the possibility of growing industrial quantities of <i>Geobacillus</i> sp. strain WSUCF1 cells as biocatalysts on reasonably inexpensive carbon sources for commercial use. This work is the first application of the adaptive laboratory evolution approach for developing the desired phenotype of enhanced ligninolytic capability in any microbial strain.https://www.mdpi.com/2076-2607/8/6/871adaptive laboratory evolutionlaccaselignocellulosic<i>Geobacillus</i>thermophile
collection DOAJ
language English
format Article
sources DOAJ
author Tanvi Govil
Priya Saxena
Dipayan Samanta
Sindhu Suresh Singh
Sudhir Kumar
David R. Salem
Rajesh K. Sani
spellingShingle Tanvi Govil
Priya Saxena
Dipayan Samanta
Sindhu Suresh Singh
Sudhir Kumar
David R. Salem
Rajesh K. Sani
Adaptive Enrichment of a Thermophilic Bacterial Isolate for Enhanced Enzymatic Activity
Microorganisms
adaptive laboratory evolution
laccase
lignocellulosic
<i>Geobacillus</i>
thermophile
author_facet Tanvi Govil
Priya Saxena
Dipayan Samanta
Sindhu Suresh Singh
Sudhir Kumar
David R. Salem
Rajesh K. Sani
author_sort Tanvi Govil
title Adaptive Enrichment of a Thermophilic Bacterial Isolate for Enhanced Enzymatic Activity
title_short Adaptive Enrichment of a Thermophilic Bacterial Isolate for Enhanced Enzymatic Activity
title_full Adaptive Enrichment of a Thermophilic Bacterial Isolate for Enhanced Enzymatic Activity
title_fullStr Adaptive Enrichment of a Thermophilic Bacterial Isolate for Enhanced Enzymatic Activity
title_full_unstemmed Adaptive Enrichment of a Thermophilic Bacterial Isolate for Enhanced Enzymatic Activity
title_sort adaptive enrichment of a thermophilic bacterial isolate for enhanced enzymatic activity
publisher MDPI AG
series Microorganisms
issn 2076-2607
publishDate 2020-06-01
description The mimicking of evolution on a laboratory timescale to enhance biocatalyst specificity, substrate utilization activity, and/or product formation, is an effective and well-established approach that does not involve genetic engineering or regulatory details of the microorganism. The present work employed an evolutionary adaptive approach to improve the lignocellulose deconstruction capabilities of the strain by inducing the expression of laccase, a multicopper oxidase, in <i>Geobacillus</i> sp. strain WSUCF1. This bacterium is highly efficient in depolymerizing unprocessed lignocellulose, needing no preprocessing/pretreatment of the biomasses. However, it natively produces low levels of laccase. After 15 rounds of serially adapting this thermophilic strain in the presence of unprocessed corn stover as the selective pressure, we recorded a 20-fold increase in catalytic laccase activity, at 9.23 ± 0.6 U/mL, in an adapted yet stable strain of <i>Geobacillus</i> sp. WSUCF1, compared with the initial laccase production (0.46 ± 0.04 U/mL) obtained with the unadapted strain grown on unprocessed corn stover before optimization. Chemical composition analysis demonstrated that lignin removal by the adapted strain was 22 wt.% compared with 6 wt.% removal by the unadapted strain. These results signify a favorable prospect for fast, cost competitive bulk production of this thermostable enzyme. Also, this work has practical importance, as this fast adaptation of the <i>Geobacillus</i> sp. strain WSUCF1 suggests the possibility of growing industrial quantities of <i>Geobacillus</i> sp. strain WSUCF1 cells as biocatalysts on reasonably inexpensive carbon sources for commercial use. This work is the first application of the adaptive laboratory evolution approach for developing the desired phenotype of enhanced ligninolytic capability in any microbial strain.
topic adaptive laboratory evolution
laccase
lignocellulosic
<i>Geobacillus</i>
thermophile
url https://www.mdpi.com/2076-2607/8/6/871
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