Publications by authors named "Sebastian Cerminati"

The implementation of cleaner technologies that minimize environmental pollution caused by conventional industrial processes is an increasing global trend. Hence, traditionally used chemicals have been replaced by novel enzymatic alternatives in a wide variety of industrial-scale processes. Enzymatic oil degumming, the first step of the oil refining process, exploits the conversion catalyzed by phospholipases to remove vegetable crude oils' phospholipids.

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Hyaluronic acid (HA) is a high value glycosaminoglycan mostly used in health and cosmetic applications. Commercial HA is produced from animal tissues or in toxigenic bacteria of the genus Streptococcus grown in complex media, which are expensive and raise environmental concerns due to the disposal of large amounts of broth with high organic loads. Other microorganisms were proposed as hosts for the heterologous production of HA, but the methods are still costly.

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The growing demand for food and biofuels urges the vegetable oil processing industry to adopt cleaner technologies to mitigate the environmental pollution caused by chemical refining processes. Over the past decade, several enzymatic methods have proven to be efficient at reducing the generated waste, but improving the benefit-cost ratio is still necessary for the widespread adoption of this technology. In this work, we show that lecithin:cholesterol acyltransferase from Aeromonas enteropelogenes (LCAT) provides a higher extra-yield of soybean oil than a type A1 phospholipase (PLA) enzyme currently commercialized for soybean oil deep degumming.

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Phospholipids play a central role in all living organisms. Phospholipases, the enzymes aimed at modifying phospholipids, are consequently widespread in nature and play diverse roles, from lipid metabolism and cellular signaling in eukaryotes to virulence and nutrient acquisition in microbes. Phospholipases catalyze the hydrolysis of one or more ester or phosphodiester bonds of glycerophospholipids.

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βγ-crystallin has emerged as a superfamily of structurally homologous proteins with representatives across all domains of life. A major portion of this superfamily is constituted by microbial members. This superfamily has also been recognized as a novel group of Ca-binding proteins with a large diversity and variable properties in Ca binding and stability.

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Extremophilic microorganisms are a rich source of enzymes, the enzymes which can serve as industrial catalysts that can withstand harsh processing conditions. An example is thermostable β-glucosidases that are addressing a challenging problem in the biodiesel industry: removing steryl glucosides (SGs) from biodiesel. Steryl glucosidases (SGases) must be tolerant to heat and solvents in order to function efficiently in biodiesel.

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Several regulatory systems contribute to bacterial resistance to heavy metals controlling the expression of factors required to eliminate the intoxicant and/or to repair the damage caused by it. In Salmonella, the response to Au ions is mediated by the specific metalloregulator GolS that, among other genes, controls the expression of the RND-efflux pump GesABC. In this work, we demonstrate that CpxR/CpxA, a main cell-envelope stress-responding system, promotes gesABC transcription in the presence of Au ions at neutral pH.

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Enzymatic degumming using phospholipase C (PLC) enzymes may be used in environmentally friendly processes with improved oil recovery yields. In this work, phosphatidylinositol-specific phospholipase C (PIPLC) candidates obtained from an in silico analysis were evaluated for oil degumming. A PIPLC from Lysinibacillus sphaericus was shown to efficiently remove phosphatidylinositol from crude oil, and when combined with a second phosphatidylcholine and phosphatidylethanolamine-specific phospholipase C, the three major phospholipids were completely hydrolyzed, providing an extra yield of oil greater than 2.

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Enzymatic oil degumming (removal of phospholipids) using phospholipase C (PLC) is a well-established and environmentally friendly process for vegetable oil refining. In this work, we report the production of recombinant Bacillus cereus PLC in Corynebacterium glutamicum ATCC 13869 in a high cell density fermentation process and its performance in soybean oil degumming. A final concentration of 5.

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Two homologous transcription factors, CueR and GolS, that belong to the MerR metalloregulatory family are responsible for Salmonella Cu and Au sensing and resistance, respectively. They share similarities not only in their sequences, but also in their target transcription binding sites. While CueR responds similarly to Au, Ag, or Cu to induce the expression of its target genes, GolS shows higher activation by Au than by Ag or Cu.

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Salmonella typhimurium harbours a Au-resistance system whose expression is controlled by GolS, a transcriptional regulator of the MerR family that selectively detects Au with high sensitivity. We developed both Salmonella and genetically engineered Escherichia coli strains as Au-selective whole-cell biosensors by coupling the strictly regulated GolS-dependent golB promoter to the gfp reporter gene. The bio-reporters were evaluated under different laboratory conditions and calibrated for their use as selective Au detectors.

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