scholarly journals Selección e identificación de una nueva bacteria productora de pectinasa a partir de fuentes geotermales

2020 ◽  
pp. 143-149
Author(s):  
Israel Salazar ◽  
Heber Ramírez ◽  
Ariadna Zúñiga ◽  
Mirella Yllanes ◽  
Ana Naquiche ◽  
...  

Los microorganismos son una fuente potencial de enzimas. Las bacterias termófilas producen enzimas termoestables, como las pectinasas, que permiten obtener una serie de productos que hidrolizan pectinas, heteropolisacáridos, componentes principales de la capa media de la pared celular de la piel de los cítricos (naranjas, limones y mandarinas), manzanas, melocotones y otros vegetales. El cultivo bacteriano productor de pectinasas se seleccionó de bacterias aisladas de géiseres de aguas termales. Las muestras se sembraron en medio líquido y sólido, se incubaron a 60 °C durante 24 a 48 horas respectivamente, observándose halos de hidrólisis como indicativos de producción de pectinasa. Las bacterias que formaron los halos se sembraron en medio de producción de pectinasas, evaluando su actividad enzimática y producción de proteínas. Se aislaron veinte cultivos bacterianos gram positivos, de los cuales 12 fueron productores de pectinasas, siendo el cultivo LBE-P4 el de mayor actividad enzimática con 0.154 U/ml y 0.069 mg/ml de proteínas totales, que fue identificado molecularmente como Geobacillus kaustophilus LBE-P4.

2003 ◽  
Author(s):  
Charles Thomas Parker ◽  
Nicole Danielle Osier ◽  
George M Garrity

2021 ◽  
Vol 547 ◽  
pp. 96-101
Author(s):  
Upasana Sridharan ◽  
Preethi Ragunathan ◽  
Seiki Kuramitsu ◽  
Shigeyuki Yokoyama ◽  
Thirumananseri Kumarevel ◽  
...  

2012 ◽  
Vol 354 (11-12) ◽  
pp. 2191-2198 ◽  
Author(s):  
Birgit Wilding ◽  
Margit Winkler ◽  
Barbara Petschacher ◽  
Regina Kratzer ◽  
Anton Glieder ◽  
...  

2009 ◽  
Vol 393 (5) ◽  
pp. 1056-1069 ◽  
Author(s):  
Kuang-Lei Tsai ◽  
Yu-Hua Lo ◽  
Yuh-Ju Sun ◽  
Chwan-Deng Hsiao

Author(s):  
Aasawari Khairnar ◽  
Sonali Sunsunwal ◽  
Ponnusamy Babu ◽  
T N C Ramya

Abstract Some bacterial flagellins are O-glycosylated on surface-exposed serine/threonine residues with nonulosonic acids such as pseudaminic acid, legionaminic acid and their derivatives by flagellin nonulosonic acid glycosyltransferases, also called motility-associated factors (Maf). We report here two new glycosidic linkages previously unknown in any organism, serine/threonine-O-linked N-acetylneuraminic acid (Ser/Thr-O-Neu5Ac) and serine/threonine-O-linked 3-deoxy-D-manno-octulosonic acid or keto-deoxyoctulosonate (Ser/Thr-O-KDO), both catalyzed by Geobacillus kaustophilus Maf and Clostridium botulinum Maf. We identified these novel glycosidic linkages in recombinant G. kaustophilus and C. botulinum flagellins that were coexpressed with their cognate recombinant Maf protein in Escherichia coli strains producing the appropriate nucleotide sugar glycosyl donor. Our finding that both G. kaustophilus Maf (putative flagellin sialyltransferase) and C. botulinum Maf (putative flagellin legionaminic acid transferase) catalyzed Neu5Ac and KDO transfer on to flagellin indicates that Maf glycosyltransferases display donor substrate promiscuity. Maf glycosyltransferases have the potential to radically expand the scope of neoglycopeptide synthesis and posttranslational protein engineering.


2012 ◽  
Vol 78 (18) ◽  
pp. 6647-6655 ◽  
Author(s):  
Yu Zhang ◽  
Jiao An ◽  
Wei Ye ◽  
Guangyu Yang ◽  
Zhi-Gang Qian ◽  
...  

ABSTRACTThe phosphotriesterase-like lactonase (PLL) enzymes in the amidohydrolase superfamily hydrolyze various lactones and exhibit latent phosphotriesterase activities. These enzymes serve as attractive templates forin vitroevolution of neurotoxic organophosphates (OPs) with hydrolytic capabilities that can be used as bioremediation tools. Here, a thermostable PLL fromGeobacillus kaustophilusHTA426 (GkaP) was targeted for joint laboratory evolution with the aim of enhancing its catalytic efficiency against OP pesticides. By a combination of site saturation mutagenesis and whole-gene error-prone PCR approaches, several improved variants were isolated. The most active variant, 26A8C, accumulated eight amino acid substitutions and demonstrated a 232-fold improvement over the wild-type enzyme in reactivity (kcat/Km) for the OP pesticideethyl-paraoxon. Concomitantly, this variant showed a 767-fold decrease in lactonase activity with δ-decanolactone, imparting a specificity switch of 1.8 × 105-fold. 26A8C also exhibited high hydrolytic activities (19- to 497-fold) for several OP pesticides, including parathion, diazinon, and chlorpyrifos. Analysis of the mutagenesis sites on the GkaP structure revealed that most mutations are located in loop 8, which determines substrate specificity in the amidohydrolase superfamily. Molecular dynamics simulation shed light on why 26A8C lost its native lactonase activity and improved the promiscuous phosphotriesterase activity. These results permit us to obtain further insights into the divergent evolution of promiscuous enzymes and suggest that laboratory evolution of GkaP may lead to potential biological solutions for the efficient decontamination of neurotoxic OP compounds.


2014 ◽  
Vol 159 (10) ◽  
pp. 2771-2775 ◽  
Author(s):  
Timothy J. Marks ◽  
Paul T. Hamilton

Microbiology ◽  
2012 ◽  
Vol 158 (8) ◽  
pp. 1942-1952 ◽  
Author(s):  
Ken-ichi Yoshida ◽  
Azusa Sanbongi ◽  
Ayano Murakami ◽  
Hirokazu Suzuki ◽  
Shinji Takenaka ◽  
...  

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