Biotransformation Of Monoterpenes Research Articles

Biotransformation of monoterpenes using Streptomyces strains from the rhizosphere of Inga edulis Martius from in an Amazonian urban forest fragment

To investigate the biocatalytic potential of Amazonian actinomycetes for monoterpenes biotransformation. To carry out the present study, eleven actinomycetes of the genus Streptomyces isolated from inga-cipó (Inga edulis Mart.) rhizospheres were tested for their ability to bioconvert the substrates R-(+)-limonene, S-(-)-limonene, 1S-(-)-α-pinene, and (-)–β–pinene as sole carbon and energy source. According to gas chromatography-mass spectrometry analysis, three strains, LabMicra B270, LaBMicrA B310, and LaBMicrA B314, were able to biotransform 1S-(-)-α-pinene after 96 h of growth. However, Streptomyces LaBMicrA B270 was the most promising since it converted after only 72 h all the 1S-(-)-α-pinene mainly into cis-verbenol (74.9±1.24%) and verbenone (18.2±1.20%), compounds that have important biological activities and great industrial interest as additives in foods and cosmetics. These findings can stimulate the development of natural aromas using naturally abundant monoterpenes, ratify the potential of microorganisms from almost unexplored niches such as the Amazonian rhizosphere, and reinforce the importance of preserving those niches.

An update on the progress of microbial biotransformation of commercial monoterpenes.

Monoterpenes, a class of isoprenoid compounds, are extensively used in flavor, fragrance, perfumery, and cosmetics. They display many astonishing bioactive properties of biological and pharmacological significance. All monoterpenes are derived from universal precursor geranyl diphosphate. The demand for new monoterpenoids has been increasing in flavor, fragrances, perfumery, and pharmaceuticals. Chemical methods, which are harmful forhuman and the environment, synthesize most of these products. Over the years, researchers have developed alternative methods for the production of newer monoterpenoids. Microbialbiotransformation is one of them, which relied onmicrobes and their enzymes. It has produced many newdesirable commercially important monoterpenoids. A growing number of reports reflect an ever-expanding scope of microbial biotransformation in food and aroma industries. Simultaneously, our knowledge of the enzymology of monoterpene biosynthetic pathways has been increasing, which facilitated the biotransformation ofmonoterpenes. In this article, we have covered the progress made on microbial biotransformation of commercial monoterpenes with a brief introduction to their biosynthesis. We have collected several reports from authentic web sources, including Google Scholar, Pubmed, Web of Science, and Scopus published in the past few years to extract information on the topic.

Production, Properties, and Applications of α-Terpineol

α-Terpineol (CAS No. 98-55-5) is a tertiary monoterpenoid alcohol widely and commonly used in the flavors and fragrances industry for its sensory properties. It is present in different natural sources, but its production is mostly based on chemical hydration using α-pinene or turpentine. Moreover, many bioprocesses for the microbial production of α-terpineol via biotransformation of monoterpenes (limonene, α- and β-pinenes) are also available in the literature. In addition to its traditional use, α-terpineol has also been evaluated in other application fields (e.g., medical), since some biological properties other than aroma, such as antioxidant, anti-inflammatory, antiproliferative, antimicrobial, and analgesic effects, among others, have been attributed to this compound. Therefore, this review presents an original compilation of data regarding the production (extraction directly from nature; chemical synthesis; via biotechnological process), the chemical and biological properties, and the current market and novel applications of α-terpineol to guide further research in this area. Considering the information presented, we believe that α-terpineol applications may transcend the flavors and fragrances industry in the future.

Biotransformation of α-Pinene to Terpineol by Resting Cell Suspension of Absidia corulea.

Microbial biotransformation of monoterpenes results in the formation of many valuable compounds. Many microorganisms can be used to carry out extremely specific conversions using substrates of low commercial value. Absidia corulea MTCC 1335 was examined for its ability to transform α-Pinene enantiomers. The substrates (-)-α-Pinene and (+)-α-Pinene converted to α-terpineol and isoterpineol, were detected in gas chromatographic analysis. The Biotransformation kinetics of the oxidized products were analysed using GC-MS. With both the substrates the products formed were similar and not much difference in the rate of transformation was observed, suggesting no enantioselectivity of organism towards the substrate.

Biotransformation of monoterpenes by immobilized microalgae

This paper reports the biotransformation of carvone, limonene, β-pinene, thymol, and linalool using whole-cell-immobilized microalgal strains isolated from paddy fields of Iran. The strains was recognized by morphological characterization and assigned according to amplified 16S/18S rRNA genes by PCR. Ten unialgal strains including Chlorella, Oocystis, Chlamydomonas, and Synechococcus were immobilized in calcium alginate beads. After a 24-h incubation with substrates, characterization and identification of biotransformation products were done by GC/MS. None of the isolated immobilized microalgae converted β-pinene. In contrast, most of these strains biotransformed carvone and limonene to the related compounds. Some strains only reduced the C = C double bond to yield the dihydrocarvone isomers while others reduced the ketone to give the dihydrocarveol. The transformation ratio showed that Oocystis sp. MCCS 033 and Synechococcus sp. MCCS 035 produced dihydrocarvone isomers with the highest efficiency. Furthermore, limonene was converted into a mixture of five corresponding products and the maximum yield was 52.1% for carvone, the bioconverted product. Only one strain, Synechococcus sp. MCCS 034, oxidized thymol, and the product obtained from thymol was thymoquinone. Also, linalooloxide isomers and dihydrolinalool were obtained from linalool, and finally dihydrolinalool was the main product. These results showed a novel conversion pathway of linalool-forming dihydrolinalool.

Microbial biotransformation of some monoterpene hydrocarbons

High commercial value compounds can be obtained through the microbial biotransformation of monoterpenes. Some of these monoterpenic substances are not expensive and produced in a variety of plant species. Biotransformation of some monoterpene hydrocarbons such as α-pinene, β-pinene, myrcene and p-cymene by 7 strain bacteria and 2 strain fungi was investigated. It was observed that some of microorganisms transformed monoterpenes to oxygenated monoterpenes in a good yield which among themStaphylococcus epidermidis showed higher yields.

Improved monoterpene biotransformation with Penicillium sp. by use of a closed gas loop bioreactor

A closed gas loop bioprocess was developed to improve fungal biotransformation of monoterpenes. By circulating monoterpene-saturated process gas, the evaporative loss of the volatile precursor from the medium during the biotransformation was avoided. Penicillium solitum, isolated from kiwi, turned out to be highly tolerant towards monoterpenes and to convert alpha-pinene to a range of products including verbenone, a valuable aroma compound. The gas loop was mandatory to reproduce the production of 35 mg L(-1) verbenone obtained in shake flasks and also in the bioreactor. Penicillium digitatum DSM 62840 regioselectively converted (+)-limonene to the aroma compound alpha-terpineol, but shake flask cultures revealed a pronounced growth inhibition when initial concentrations exceeded 1.9 mM. In the bioreactor, toxic effects on P. digitatum during biotransformation were alleviated by starting a sequential feeding of non-toxic limonene portions after a preceding growth phase. Closing the precursor-saturated gas loop during the biotransformation allowed for an additional replenishment of limonene via the gas phase. The gas loop system led to a maximum alpha-terpineol concentration of 1,009 mg L(-1) and an average productivity of 8-9 mg L(-1) h(-1) which represents a doubling of the respective values previously reported. Furthermore, a molar conversion yield of up to 63% was achieved.

Biotransformation of monoterpenes by Oocystis pusilla

The biotransformation of several monoterpenes by the locally isolated unicellular microalga, Oocystis pusilla was investigated. The metabolites were identified by thin layer chromatography and GC/MS. The results showed that O. pusilla had the ability to reduce the C=C double bond in (+)-carvone to yield trans-dihydrocarvone and traces of cis-dihydrocarvone. O. pusilla also converted (+)-limonene to trans-carveol, as the main product, and yielded carvone and trans-limonene oxide. Furthermore, (−)-linalool was converted to trans-furanoid and trans-pyranoid linalool oxide, thymol was converted to thymoquinone, (−)-carveol was converted to carvone and trans-dihydrocarvone, (−)-menthone and (+)-pulegone were converted to menthol, (L)-citronellal was converted to citronellol, and (+)-β-pinene was converted to trans-pinocarveol.

Biotransformation of a Monoterpene Mixture by in vitro Cultures of Selected Conifer Species

Biotransformation of monoterpenes is a mild and promising method for the production of stereospecific and regiospecific organic compounds. It is advantageous, especially for the preparation of substances with complicated structures and for those that need to be classed as “natural products“. Our study has focused on the biotransformation of a monoterpenic mixture, turpentine, by Picea abies and Taxus baccata suspension cultures. We identified the biotransformation products and compared the metabolite compositions of the tissue cultures. The major biotransformation products of turpentine were trans-pinocarveol, trans-verbenol, verbenone, myrtenol, α-terpineol and trans-sobrerol, which correspond with the products of biotransformation of the individual monoterpenes, α-pinene and β-pinene, by P. abies suspension culture.

Biotransformation of selected monoterpenes under nitrate-reducing conditions

Batch experiments were conducted to assess both the biotransformation potentials of one hydrocarbon (α-pinene) and four alcohol monoterpenes (arbanol, linalool, plinol, and α-terpineol) under nitrate-reducing conditions at 23 °C, as well as their effects on the nitrate-reducing process. A mixed, nitrate-reducing culture developed from a forest-soil extract was enriched using ethanol as the electron donor and used in this study. α-Pinene was not biotransformed under the conditions of this study and inhibited both ethanol and nitrate utilization. Partial transformation of the alcohol monoterpenes was observed and resulted in inhibition of the nitrate-reducing process and cessation of further utilization of the added monoterpenes. Accumulation of biotransformation products – mainly hydrocarbon monoterpenes such as camphene, β-myrcene, and d-limonene – was observed. The hydrocarbon monoterpenes formed may have been responsible for the observed inhibition of the nitrate-reducing process and lack of complete utilization of the alcohol monoterpenes. These results have significant implications for the expected rate and extent of biotransformation of monoterpenes under anoxic conditions as well as their effect on the nitrate-reducing process in both engineered and natural systems.

Biotransformation of monoterpenes, bile acids, and other isoprenoids in anaerobic ecosystems

Isoprenoic compounds play a major part in the global carbon cycle. Biosynthesis and mineralization by aerobic bacteria have been intensively studied. This review describes our knowledge on the anaerobic metabolism of isoprenoids, mainly by denitrifying and fermentative bacteria. Nitrate-reducing β-Proteobacteria were isolated on monoterpenes as sole carbon source and electron donor. Thauera spp. were obtained on the oxygen-containing monoterpenes linalool, menthol, and eucalyptol. Several strains of Alcaligenes defragrans were isolated on unsaturated monoterpenes as growth substrates. A novel denitrifying β-Proteobacterium, strain 72Chol, mineralizes cholesterol completely to carbon dioxide. Physiological studies showed the presence of several oxidative pathways in these microorganisms. Investigations by organic geochemists indicate possible contributions of anaerobes to early diagenetic processes. One example, the formation of p-cymene from monoterpenes, could indeed be detected in methanogenic enrichment cultures. In man, cholic acid (CA) and chenodeoxycholic acid (CDCA), are synthesized in the liver from cholesterol. During their enterohepatic circulation, bile acids are biotransformed by the intestinal microflora into a variety of metabolites. Known bacterial biotransformations of conjugated bile acids include: deconjugation, oxidation of hydroxy groups at C-3, C-7 and C-12 with formation of oxo bile acids and reduction of these oxo groups to either α- or β-configuration. Quantitatively, the most important bacterial biotransformation is the 7α-dehydroxylation of CA and CDCA yielding deoxycholic acid and lithocholic acid, respectively. The 7α-dehydroxylation of CA occurs via a novel six-step biochemical pathway. The genes encoding several enzymes that either transport bile acids or catalyze various reactions in the 7α-dehydroxylation pathway of Eubacterium sp. strain VPI 12708 have been cloned, expressed in Escherichia coli, purified, and characterized.

Biotransformation of monoterpenes, bile acids, and other isoprenoids in anaerobic ecosystems.

Isoprenoic compounds play a major part in the global carbon cycle. Biosynthesis and mineralization by aerobic bacteria have been intensively studied. This review describes our knowledge on the anaerobic metabolism of isoprenoids, mainly by denitrifying and fermentative bacteria. Nitrate-reducing beta-Proteobacteria were isolated on monoterpenes as sole carbon source and electron donor. Thauera spp. were obtained on the oxygen-containing monoterpenes linalool, menthol, and eucalyptol. Several strains of Alcaligenes defragrans were isolated on unsaturated monoterpenes as growth substrates. A novel denitrifying beta-Proteobacterium, strain 72Chol, mineralizes cholesterol completely to carbon dioxide. Physiological studies showed the presence of several oxidative pathways in these microorganisms. Investigations by organic geochemists indicate possible contributions of anaerobes to early diagenetic processes. One example, the formation of p-cymene from monoterpenes, could indeed be detected in methanogenic enrichment cultures. In man, cholic acid (CA) and chenodeoxycholic acid (CDCA), are synthesized in the liver from cholesterol. During their enterohepatic circulation, bile acids are biotransformed by the intestinal microflora into a variety of metabolites. Known bacterial biotranformations of conjugated bile acids include: deconjugation, oxidation of hydroxy groups at C-3, C-7 and C-12 with formation of oxo bile acids and reduction of these oxo groups to either alpha- or beta-configuration. Quantitatively, the most important bacterial biotransformation is the 7 alpha-dehydroxylation of CA and CDCA yielding deoxycholic acid and lithocholic acid, respectively. The 7 alpha-dehydroxylation of CA occurs via a novel six-step biochemical pathway. The genes encoding several enzymes that either transport bile acids or catalyze various reactions in the 7 alpha-dehydroxylation pathway of Eubacterium sp. strain VPI 12708 have been cloned, expressed in Escherichia coli, purified, and characterized.

Biotransformation of Monoterpenes by Polyurethane Foam-Immobilized Cells of Petroselinum crispum (Mill) Nyman

Abstract Cells of Petroselinum crispum cv. “Paramount” and “Plain-leaved” immobilized in polyurethane foam retained the biotransformational characteristics of their freely suspended cells for certain monoterpenic substrates. Immobilized cells of both cultivars were more efficient than their free cells in isomerizing geraniol into nerol, but less efficient (<60% ) in reducing the aldehydes, citral and citronellal. Maintenance of the immobilized cells under the condition of growth limitation did not enhance the efficiency of the biochemical reactions. Under the same condition, the freely suspended cells of cult. “Paramount” exhibited higher efficiency (up to 1.6 times) of biotransformation of citral when compared to those in sucrose-supplemented media. This investigation lends support to the view that the biochemical productivity of cultured plant cells for especially monoterpenoids may not necessarily be improved upon immobilization.

Biotransformation of Monoterpenes by Mentha Cell Lines

Previous results indicated that all tested cell suspension lines derived from various Mentha chemotypes were capable to biotransform (-) menthone to (+)-neomentol but only some of these lines converted (+)-pulegone to (+)-isomenthone. In order to quest whether only the natural secondary metabolites or also other compounds with similarities to pulegone are biohydrogenated by Mentha cell suspensions, we incubated such suspensions with 5 unsaturated alpha-beta; ketones. No conversion was detected when mesityl oxide, trans-6-tert. butyl pulegone or 3-isopropylidine-9-methyl-decalone-2 were incubated with Mentha cells, while saturation of the alpha-beta double bond of 2-isopropylidine cyclohexanone and of trans-6-methyl pulegone was observed in suspensions of those cell lines which are capable of pulegone transformation. Suspensions of Mentha cell lines which were incapable to hydrogenate pulegone did not biotransform the two latter pulegone analogues.

Biotransformation of Monoterpenes by Mentha Cell Lines: Conversion of Menthone to Neomenthol

Following previous results, which indicated that cell lines derived from different Mentha chemotypes were either capable or not capable to biotransform pulegone into isomenthone, we studied menthone biotransformation by in vitro cultured Mentha cell lines. All the six cell lines did transform (-)-menthone into another monoterpene. The latter was identified by GLC, TLC and NMR techniques as (+)-neomenthol. None of these cell lines reduced (+)-isomenthoneto the corresponding alcohol. These results indicate a stereospecificity in respect to both precursor and product in this plant cell biotransformation system.

Biotransformation of monoterpenes by mentha cell lines: conversion of pulegone to isomenthone.

Following previous results, which indicated that cell lines derived from different Mentha chemotypes were either capable or not capable to biotransform pulegone into isomenthone, we studied menthone biotransformation by in vitro cultured Mentha cell lines. All the six cell lines did transform (-)-menthone into another monoterpene. The latter was identified by GLC, TLC and NMR techniques as (+)-neomenthol. None of these cell lines reduced (+)-isomenthoneto the corresponding alcohol. These results indicate a stereospecificity in respect to both precursor and product in this plant cell biotransformation system.