scholarly journals Application of Microalgal Stress Responses in Industrial Microalgal Production Systems

Marine Drugs ◽  
2021 ◽  
Vol 20 (1) ◽  
pp. 30
Author(s):  
Jia Wang ◽  
Yuxin Wang ◽  
Yijian Wu ◽  
Yuwei Fan ◽  
Changliang Zhu ◽  
...  
Keyword(s):  
Stress Responses ◽  
Production Systems ◽  
Strain Improvement ◽  
Value Added ◽  
Product Yield ◽  
Adaptive Laboratory Evolution ◽  
Laboratory Evolution ◽  
Theoretical Support ◽  
Further Development ◽  
Value Added Products

Adaptive laboratory evolution (ALE) has been widely utilized as a tool for developing new biological and phenotypic functions to explore strain improvement for microalgal production. Specifically, ALE has been utilized to evolve strains to better adapt to defined conditions. It has become a new solution to improve the performance of strains in microalgae biotechnology. This review mainly summarizes the key results from recent microalgal ALE studies in industrial production. ALE designed for improving cell growth rate, product yield, environmental tolerance and wastewater treatment is discussed to exploit microalgae in various applications. Further development of ALE is proposed, to provide theoretical support for producing the high value-added products from microalgal production.

scholarly journals Systems biology and metabolic engineering of Rhodococcus for bioconversion and biosynthesis processes

2021 ◽  
Author(s):  
Eva Donini ◽  
Andrea Firrincieli ◽  
Martina Cappelletti
Keyword(s):  
Renewable Resources ◽  
Rational Design ◽  
Low Cost ◽  
Value Added ◽  
Adaptive Laboratory Evolution ◽  
Toxic Compounds ◽  
Laboratory Evolution ◽  
Metabolic Versatility ◽  
Genomic Basis ◽  
Value Added Products

AbstractRhodococcus spp. strains are widespread in diverse natural and anthropized environments thanks to their high metabolic versatility, biodegradation activities, and unique adaptation capacities to several stress conditions such as the presence of toxic compounds and environmental fluctuations. Additionally, the capability of Rhodococcus spp. strains to produce high value-added products has received considerable attention, mostly in relation to lipid accumulation. In relation with this, several works carried out omic studies and genome comparative analyses to investigate the genetic and genomic basis of these anabolic capacities, frequently in association with the bioconversion of renewable resources and low-cost substrates into triacylglycerols. This review is focused on these omic analyses and the genetic and metabolic approaches used to improve the biosynthetic and bioconversion performance of Rhodococcus. In particular, this review summarizes the works that applied heterologous expression of specific genes and adaptive laboratory evolution approaches to manipulate anabolic performance. Furthermore, recent molecular toolkits for targeted genome editing as well as genome-based metabolic models are described here as novel and promising strategies for genome-scaled rational design of Rhodococcus cells for efficient biosynthetic processes application.

scholarly journals Efficient production of d-lactate from methane in a lactate-tolerant strain of Methylomonas sp. DH-1 generated by adaptive laboratory evolution

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Jong Kwan Lee ◽  
Sujin Kim ◽  
Wonsik Kim ◽  
Sungil Kim ◽  
Seungwoo Cha ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Lactic Acid ◽  
Lactate Dehydrogenase ◽  
Value Added ◽  
Wild Type ◽  
Adaptive Laboratory Evolution ◽  
Gene Encoding ◽  
Laboratory Evolution ◽  
Tolerant Strain ◽  
Dehydrogenase Gene

Abstract Background Methane, a main component of natural gas and biogas, has gained much attention as an abundant and low-cost carbon source. Methanotrophs, which can use methane as a sole carbon and energy source, are promising hosts to produce value-added chemicals from methane, but their metabolic engineering is still challenging. In previous attempts to produce lactic acid (LA) from methane, LA production levels were limited in part due to LA toxicity. We solved this problem by generating an LA-tolerant strain, which also contributes to understanding novel LA tolerance mechanisms. Results In this study, we engineered a methanotroph strain Methylomonas sp. DH-1 to produce d-lactic acid (d-LA) from methane. LA toxicity is one of the limiting factors for high-level production of LA. Therefore, we first performed adaptive laboratory evolution of Methylomonas sp. DH-1, generating an LA-tolerant strain JHM80. Genome sequencing of JHM80 revealed the causal gene watR, encoding a LysR-type transcription factor, whose overexpression due to a 2-bp (TT) deletion in the promoter region is partly responsible for the LA tolerance of JHM80. Overexpression of the watR gene in wild-type strain also led to an increase in LA tolerance. When d form-specific lactate dehydrogenase gene from Leuconostoc mesenteroides subsp. mesenteroides ATCC 8293 was introduced into the genome while deleting the glgA gene encoding glycogen synthase, JHM80 produced about 7.5-fold higher level of d-LA from methane than wild type, suggesting that LA tolerance is a critical limiting factor for LA production in this host. d-LA production was further enhanced by optimization of the medium, resulting in a titer of 1.19 g/L and a yield of 0.245 g/g CH4. Conclusions JHM80, an LA-tolerant strain of Methylomonas sp. DH-1, generated by adaptive laboratory evolution was effective in LA production from methane. Characterization of the mutated genes in JHM80 revealed that overexpression of the watR gene, encoding a LysR-type transcription factor, is responsible for LA tolerance. By introducing a heterologous lactate dehydrogenase gene into the genome of JHM80 strain while deleting the glgA gene, high d-LA production titer and yield were achieved from methane.

scholarly journals Special Issue “Lignocellulosic Biomass”

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1483
Author(s):  
Alejandro Rodríguez ◽  
Eduardo Espinosa
Keyword(s):  
Lignocellulosic Biomass ◽  
Production Systems ◽  
Value Added ◽  
Raw Material ◽  
Special Issue ◽  
Value Added Products

The use of lignocellulosic biomass as potential raw material for fractionation and transformation into high value-added products or energy is gathering the attention of scientists worldwide in seeking to achieve a green transition in our production systems [...]

scholarly journals Towards Higher Rate Electrochemical CO2 Conversion: From Liquid-Phase to Gas-Phase Systems

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 224 ◽  
Author(s):  
Jun Song ◽  
Hakhyeon Song ◽  
Beomil Kim ◽  
Jihun Oh
Keyword(s):  
Liquid Phase ◽  
Gas Phase ◽  
Co2 Reduction ◽  
Value Added ◽  
Co2 Conversion ◽  
Co2 Solubility ◽  
Low Co2 ◽  
Phase Systems ◽  
Further Development ◽  
Value Added Products

Electrochemical CO2 conversion offers a promising route for value-added products such as formate, carbon monoxide, and hydrocarbons. As a result of the highly required overpotential for CO2 reduction, researchers have extensively studied the development of catalyst materials in a typical H-type cell, utilizing a dissolved CO2 reactant in the liquid phase. However, the low CO2 solubility in an aqueous solution has critically limited productivity, thereby hindering its practical application. In efforts to realize commercially available CO2 conversion, gas-phase reactor systems have recently attracted considerable attention. Although the achieved performance to date reflects a high feasibility, further development is still required in order for a well-established technology. Accordingly, this review aims to promote the further study of gas-phase systems for CO2 reduction, by generally examining some previous approaches from liquid-phase to gas-phase systems. Finally, we outline major challenges, with significant lessons for practical CO2 conversion systems.

Strain improvement of Chlorella sp. for phenol biodegradation by adaptive laboratory evolution

2016 ◽  
Vol 205 ◽  
pp. 264-268 ◽  
Author(s):  
Libo Wang ◽  
Chuizhao Xue ◽  
Liang Wang ◽  
Quanyu Zhao ◽  
Wei Wei ◽  
...  
Keyword(s):  
Strain Improvement ◽  
Adaptive Laboratory Evolution ◽  
Phenol Biodegradation ◽  
Laboratory Evolution ◽  
Chlorella Sp

scholarly journals Harnessing the Power of Mutagenesis and Adaptive Laboratory Evolution for High Lipid Production by Oleaginous Microalgae and Yeasts

2020 ◽  
Vol 12 (12) ◽  
pp. 5125
Author(s):  
Neha Arora ◽  
Hong-Wei Yen ◽  
George P. Philippidis
Keyword(s):  
Genetic Engineering ◽  
Lipid Production ◽  
Random Mutagenesis ◽  
Strain Improvement ◽  
Production Costs ◽  
Screening Methods ◽  
Scale Production ◽  
Adaptive Laboratory Evolution ◽  
Laboratory Evolution ◽  
Oleaginous Microalgae

Oleaginous microalgae and yeasts represent promising candidates for large-scale production of lipids, which can be utilized for production of drop-in biofuels, nutraceuticals, pigments, and cosmetics. However, low lipid productivity and costly downstream processing continue to hamper the commercial deployment of oleaginous microorganisms. Strain improvement can play an essential role in the development of such industrial microorganisms by increasing lipid production and hence reducing production costs. The main means of strain improvement are random mutagenesis, adaptive laboratory evolution (ALE), and rational genetic engineering. Among these, random mutagenesis and ALE are straight forward, low-cost, and do not require thorough knowledge of the microorganism’s genetic composition. This paper reviews available mutagenesis and ALE techniques and screening methods to effectively select for oleaginous microalgae and yeasts with enhanced lipid yield and understand the alterations caused to metabolic pathways, which could subsequently serve as the basis for further targeted genetic engineering.

scholarly journals Multiple Optimal Phenotypes Overcome Redox and Glycolytic Intermediate Metabolite Imbalances inEscherichia coli pgiKnockout Evolutions

2018 ◽  
Vol 84 (19) ◽  
Author(s):  
Douglas McCloskey ◽  
Sibei Xu ◽  
Troy E. Sandberg ◽  
Elizabeth Brunk ◽  
Ying Hefner ◽  
...  
Keyword(s):  
Gene Product ◽  
Stress Responses ◽  
Major Gene ◽  
Valuable Insight ◽  
Adaptive Laboratory Evolution ◽  
Glycolytic Intermediate ◽  
Laboratory Evolution ◽  
Content Type ◽  
Mechanistic Understanding ◽  
K 12

ABSTRACTA mechanistic understanding of how new phenotypes develop to overcome the loss of a gene product provides valuable insight on both the metabolic and regulatory functions of the lost gene. Thepgigene, whose product catalyzes the second step in glycolysis, was deleted in a growth-optimizedEscherichia coliK-12 MG1655 strain. The initial knockout (KO) strain exhibited an 80% drop in growth rate that was largely recovered in eight replicate, but phenotypically distinct, cultures after undergoing adaptive laboratory evolution (ALE). Multi-omic data sets showed that the loss ofpgisubstantially shifted pathway usage, leading to a redox and sugar phosphate stress response. These stress responses were overcome by unique combinations of innovative mutations selected for by ALE. Thus, the coordinated mechanisms from genome to metabolome that lead to multiple optimal phenotypes after the loss of a major gene product were revealed.IMPORTANCEA mechanistic understanding of how microbes are able to overcome the loss of a gene through regulatory and metabolic changes is not well understood. Eight independent adaptive laboratory evolution (ALE) experiments withpgiknockout strains resulted in eight phenotypically distinct endpoints that were able to overcome the gene loss. Utilizing multi-omics analysis, the coordinated mechanisms from genome to metabolome that lead to multiple optimal phenotypes after the loss of a major gene product were revealed.

scholarly journals Plastic Fuel Conversion and Characterisation: A Waste Valorization Potential for Ghana

MRS Advances ◽  
2020 ◽  
Vol 5 (26) ◽  
pp. 1349-1356
Author(s):  
Michael Commeh ◽  
David Dodoo-Arhin ◽  
Edward Acquaye ◽  
Isaiah Nimako Baah ◽  
Nene Kwabla Amoatey ◽  
...  
Keyword(s):  
Liquid Product ◽  
Value Added ◽  
Product Yield ◽  
Waste Valorization ◽  
Fuel Conversion ◽  
Plastic Materials ◽  
Liquid Products ◽  
Pyrolysis Reactor ◽  
Pyrolytic Oil ◽  
Value Added Products

AbstractPlastics generally play a very important role in a plethora of industries, fields and our everyday lives. In spite of their cheapness, availability and important contributions to lives, they however, pose a serious threat to the environment due to their mostly non-biodegradable nature. Recycling into useful products can reduce the amount of plastic waste. Thermal degradation (Pyrolysis) of plastics is becoming an increasingly important recycling method for the conversion of plastic materials into valuable chemicals and oil products. In this work, waste Polyethylene terephthalate (PET) water bottles were thermally converted into useful gaseous and liquid products. A simple pyrolysis reactor system has been used for the conversions with the liquid product yield of 65 % at a temperature range of 400°C to 550°C. The chemical analysis of the pyrolytic oil showed the presence of functional groups such as alkanes, alkenes, alcohols, ethers, carboxylic acids, esters, and phenyl ring substitution bands. The main constituents were 1-Tetradecene, 1-Pentadecene, Cetene, Hexadecane, 1-Heptadecene, Heptadecane, Octadecane, Nonadecane, Eicosane, Tetratetracontane, 1-Undecene, 1-Decene). The results are promising and can be maximized by additional techniques such as hydrogenation and hydrodeoxygenation to obtain value-added products.

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