A number of bacterial lipases can be immobilized in a rapid and strong fashion on octyl-agarose gels (e.g., lipases from Candida antarctica, Pseudomonas fluorescens, Rhizomucor miehei, Humicola lanuginosa, Mucor javanicus, and Rhizopus niveus). Adsorption rates in absence of ammonium sulfate are higher than in its presence, opposite to the observation for typical hydrophobic adsorption of proteins. At 10 mM phosphate, adsorption of lipases is fairly selective allowing enzyme purification associated with their reversible immobilization. Interestingly, these immobilized lipase molecules show a dramatic hyperactivation. For example, lipases from R. niveus, M. miehei, and H. lanuginosa were 6-, 7-, and 20-fold more active than the corresponding soluble enzymes when catalyzing the hydrolysis of a fully soluble substrate (0.4 mM p-nitrophenyl propionate). Even higher hyperactivations and interesting changes in stereospecificity were also observed for the hydrolysis of larger soluble chiral esters (e.g. (R,S)-2-hydroxy-4-phenylbutanoic ethyl ester). These results suggest that lipases recognize these "well-defined" hydrophobic supports as solid interfaces and they become adsorbed through the external areas of the large hydrophobic active centers of their "open and hyperactivated structure". This selective interfacial adsorption of lipases becomes a very promising immobilization method with general application for most lipases. Through this method, we are able to combine, via a single and easily performed adsorption step, the purification, the strong immobilization, and a dramatic hyperactivation of lipases acting in the absence of additional interfaces, (e.g., in aqueous medium with soluble substrate). Copyright 1998 John Wiley & Sons, Inc.

A single step purification, immobilization, and hyperactivation of lipases via interfacial adsorption on strongly hydrophobic supports

Immobilization of lipases by selective adsorption on hydrophobic supports.

Production of industrial chemicals using renewable biomass feedstock is becoming increasingly important to address limited fossil resources, climate change and other environmental problems. To develop high-performance microbial cell factories, equivalent to chemical plants, microorganisms undergo systematic metabolic engineering to efficiently convert biomass-derived carbon sources into target chemicals. Over the past two decades, many engineered microorganisms capable of producing natural and non-natural chemicals have been developed. This Review details the current status of representative industrial chemicals that are produced through biological and/or chemical reactions. We present a comprehensive bio-based chemicals map that highlights the strategies and pathways of single or multiple biological reactions, chemical reactions and combinations thereof towards production of particular chemicals of interest. Future challenges are also discussed to enable production of even more diverse chemicals and more efficient production of chemicals from renewable feedstocks.

A comprehensive metabolic map for production of bio-based chemicals

Lipases are endowed with a substrate specificity that surpasses that of any other known enzyme. This confers on these enzymes an application potential that is literally boundless. Lipases can be employed in the production of pharmaceuticals, cosmetics, leather, detergents, foods, perfumery, medical diagnostics, and other organic synthetic materials. This review attempts to present a comprehensive discussion on the present status of this unique group of enzymes in industry, as well as the actual potential. It represents an endeavor to provide a sincere answer to the question, “What can be done with this enzyme?” as well as, “Can lipase be utilized for this purpose?” It is intended that the manuscript will cover or at least mention all known applications, based on the exploitation of a particular type of reaction catalyzed by lipases. An attempt will be made to cover as large a number of references as possible, so as to further underline the importance and significance of lipase action for industry.

Applications of lipase

The microbiota consists of a dynamic multispecies community of bacteria, fungi, archaea, and protozoans, bringing to the host organism a dowry of cells and genes more numerous than its own. Among the different non-sterile cavities, the human gut harbors the most complex microbiota, with a strong impact on host homeostasis and immunostasis, being thus essential for maintaining the health condition. In this review, we outline the roles of gut microbiota in immunity, starting with the background information supporting the further presentation of the implications of gut microbiota dysbiosis in host susceptibility to infections, hypersensitivity reactions, autoimmunity, chronic inflammation, and cancer. The role of diet and antibiotics in the occurrence of dysbiosis and its pathological consequences, as well as the potential of probiotics to restore eubiosis is also discussed.

/pdf/aspects-of-gut-microbiota-and-immune-system-interactions-in-1lghypxsxu.pdf

Aspects of Gut Microbiota and Immune System Interactions in Infectious Diseases, Immunopathology, and Cancer.

Systems Metabolic Engineering Strategies: Integrating Systems and Synthetic Biology with Metabolic Engineering

https://www.cell.com/trends/biotechnology/pdf/S0167-7799(19)30277-X.pdf

Metabolic Engineering of Escherichia coli for Natural Product Biosynthesis

CRISPR/Cas9-coupled recombineering for metabolic engineering of Corynebacterium glutamicum

Malonyl-CoA is an important central metabolite for the production of diverse valuable chemicals including natural products, but its intracellular availability is often limited due to the competition with essential cellular metabolism Several malonyl-CoA biosensors have been developed for high-throughput screening of targets increasing the malonyl-CoA pool However, they are limited for use only in Escherichia coli and Saccharomyces cerevisiae and require multiple signal transduction steps Here we report development of a colorimetric malonyl-CoA biosensor applicable in three industrially important bacteria: E coli, Pseudomonas putida, and Corynebacterium glutamicum RppA, a type III polyketide synthase producing red-colored flaviolin, was repurposed as a malonyl-CoA biosensor in E coli Strains with enhanced malonyl-CoA accumulation were identifiable by the colorimetric screening of cells showing increased red color Other type III polyketide synthases could also be repurposed as malonyl-CoA biosensors For target screening, a 1,858 synthetic small regulatory RNA library was constructed and applied to find 14 knockdown gene targets that generally enhanced malonyl-CoA level in E coli These knockdown targets were applied to produce two polyketide (6-methylsalicylic acid and aloesone) and two phenylpropanoid (resveratrol and naringenin) compounds Knocking down these genes alone or in combination, and also in multiple different E coli strains for two polyketide cases, allowed rapid development of engineered strains capable of enhanced production of 6-methylsalicylic acid, aloesone, resveratrol, and naringenin to 4403, 309, 518, and 1038 mg/L, respectively The malonyl-CoA biosensor developed here is a simple tool generally applicable to metabolic engineering of microorganisms to achieve enhanced production of malonyl-CoA–derived chemicals

https://www.pnas.org/content/pnas/115/40/9835.full.pdf

Repurposing type III polyketide synthase as a malonyl-CoA biosensor for metabolic engineering in bacteria

Natural products have been attracting much interest around the world for their diverse applications, especially in drug and food industries. Plants have been a major source of many different natural products. However, plants are affected by weather and environmental conditions and their successful extraction is rather limited. Chemical synthesis is inefficient due to the complexity of their chemical structures involving enantioselectivity and regioselectivity. For these reasons, an alternative means of overproducing valuable natural products using microorganisms has emerged. In recent years, various metabolic engineering strategies have been developed for the production of natural products by microorganisms. Here, the strategies taken to produce natural products are reviewed. For convenience, natural products are classified into four main categories: terpenoids, phenylpropanoids, polyketides, and alkaloids. For each product category, the strategies for establishing and rewiring the metabolic network for heterologous natural product biosynthesis, systems approaches undertaken to optimize production hosts, and the strategies for fermentation optimization are reviewed. Taken together, metabolic engineering has enabled microorganisms to serve as a prominent platform for natural compounds production. This article examines both the conventional and novel strategies of metabolic engineering, providing general strategies for complex natural compound production through the development of robust microbial‐cell factories.

Dongsoo Yang

Papers

Systems Metabolic Engineering Strategies: Integrating Systems and Synthetic Biology with Metabolic Engineering

Metabolic Engineering of Escherichia coli for Natural Product Biosynthesis

CRISPR/Cas9-coupled recombineering for metabolic engineering of Corynebacterium glutamicum

Repurposing type III polyketide synthase as a malonyl-CoA biosensor for metabolic engineering in bacteria

Metabolic Engineering of Microorganisms for the Production of Natural Compounds