Historical and Recent Achievements in the Field of Microbial Degradation of Natural and Synthetic Rubber

Yikmis, Meral; Steinbüchel, Alexander

doi:10.1128/aem.00001-12

Cited by 86 publications

(39 citation statements)

References 51 publications

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“…Lcp is widespread in Gram-positive rubber degraders and is unrelated to RoxA; Lcps have a significantly different molecular mass of about 42 kDa, compared to Ϸ72 kDa for RoxAs. The amino acid sequences of Lcps have no heme binding motifs that could serve as covalent attachment sites for heme groups, and Lcps cleave rubber to larger degradation products than RoxAs (6,15,16). Recently, the Lcp proteins of two species (Streptomyces sp.…”

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“…Most of these materials are released to the environment in the form of waste or by abrasion in the case of tires. As a natural compound, rubber is a fully biodegradable material, and many rubber-degrading microorganisms have been isolated from various ecosystems in the past (1)(2)(3)(4)(5)(6)(7)(8). The initial step of rubber biodegradation is the enzymatic cleavage of the polymeric carbon backbone to smaller products.…”

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Latex Clearing Protein (Lcp) of Streptomyces sp. Strain K30 Is a b -Type Cytochrome and Differs from Rubber Oxygenase A (RoxA) in Its Biophysical Properties

Birke

Röther

Jendrossek

2015

Appl Environ Microbiol

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Specific polyisoprene-cleaving activities of 1.5 U/mg and 4.6 U/mg were determined for purified Strep-tagged latex clearing protein (Lcp) of Streptomyces sp. strain K30 at 23°C and 37°C, respectively. Metal analysis revealed the presence of approximately one atom of iron per Lcp molecule. Copper, which had been identified in Lcp1 VH2 of Gordonia polyisoprenivorans previously, was below the detection limit in Lcp K30 . Heme was identified as a cofactor in purified Lcp K30 by (i) detection of characteristic ␣-, ␤-, and ␥ (Soret)-bands at 562 nm, 532 nm, and 430 nm in the visible spectrum after chemical reduction, (ii) detection of an acetoneextractable porphyrin molecule, (iii) determination of a heme b-type-specific absorption maximum (556 nm) after chemical conversion of the heme group to a bipyridyl-heme complex, and (iv) detection of a b-heme-specific m/z value of 616.2 via mass spectrometry. Spectroscopic analysis showed that purified Lcp as isolated contains an oxidized heme-Fe 3؉ that is free of bound dioxygen. This is in contrast to the rubber oxygenase RoxA, a c-type heme-containing polyisoprene-cleaving enzyme present in Gram-negative rubber degraders, in which the covalently bound heme firmly binds a dioxygen molecule. Lcp K30 also differed from RoxA in the lengths of the rubber degradation cleavage products and in having a higher melting point of 61.5°C (RoxA, 54.3°C). In summary, RoxA and Lcp both are equipped with a heme cofactor and catalyze an oxidative C-C cleavage reaction but differ in the heme subgroup type and in several biochemical and biophysical properties. These findings suggest differences in the catalytic reaction mechanisms.T he hydrocarbon natural rubber [poly(cis-1,4-isoprene)] is an important biopolymer that is produced by many plants and some fungi. Natural rubber, as well as chemically synthesized poly(cis-1,4-isoprene) (synthetic rubber), has been in use by mankind for more than 100 years. Huge amounts of rubber derived from the rubber tree Hevea brasiliensis are the basis for the manufacturing of tires, sealers, latex gloves, condoms, and many other items. Most of these materials are released to the environment in the form of waste or by abrasion in the case of tires. As a natural compound, rubber is a fully biodegradable material, and many rubber-degrading microorganisms have been isolated from various ecosystems in the past (1-8). The initial step of rubber biodegradation is the enzymatic cleavage of the polymeric carbon backbone to smaller products. Two types of rubber-cleaving enzymes have been characterized so far. One is rubber oxygenase A, RoxA, which is found in Gram-negative clearing zone formers. The other is latex clearing protein, Lcp, which has been identified only in Gram-positive organisms so far. RoxA first was isolated and biochemically characterized from Xanthomonas sp. strain 35Y (9). Biochemical and biophysical investigation revealed that RoxA is an extracellular dioxygenase with two covalently attached heme groups (10, 11) and is structurally but not functio...

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confidence: 99%

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confidence: 99%

Latex Clearing Protein (Lcp) of Streptomyces sp. Strain K30 Is a b -Type Cytochrome and Differs from Rubber Oxygenase A (RoxA) in Its Biophysical Properties

Birke

Röther

Jendrossek

2015

Appl Environ Microbiol

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“…Isolate F5 and F7 were identified as Gram-positive and others were Gram-negative bacteria. All ten isolates did not produce clearing zone around the colonies indicated that they could degrade the latex concentrate by a production of an intracellular enzyme [16].…”

Section: A Isolation Of Rubber-degrading Microorganisms From Soil Samentioning

confidence: 99%

“…These polymers can be used in thousands of ways i.e. in the fabrics, mining, power generation, agriculture, transportation, paper industries, insulation of cables, wires, and various equipments, in addition, it is the major component in rubber tires [16]. However, billions of discarded tires are currently stockpiled around the world and these are increasing exponentially and causing important environmental problems.…”

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Comparative Studies on Rubber Biodegradation by Mixed Culture and Pure Culture Isolated From the Soil Samples

2017

IJAAEE

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Abstract-An increasing production of natural rubber (NR) compounds has led to major challenges in waste management. The degradation of NR is normally extremely slow. In this study, the degradation of rubber latex gloves in a mineral salt medium (MSM) using a mixed culture of the selected bacteria and a pure culture was investigated by monitoring weight loss, scanning electron microscopy (SEM) and viable cell counts. About 18% weight loss of the rubber gloves were detected after incubated with the mixed culture and the pure culture. The increased viable cell counts over incubation time indicated that cells used rubber gloves as a carbon source leading to the degradation of the polymer. The degradation of NR gloves was also determined by observing the growth of NR-degrading bacteria on the glove surface using SEM.

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Recycling of Rubber

Swapna

Stephen

2016

Recycling of Polymers

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Historical and Recent Achievements in the Field of Microbial Degradation of Natural and Synthetic Rubber

Cited by 86 publications

References 51 publications

Latex Clearing Protein (Lcp) of Streptomyces sp. Strain K30 Is a b -Type Cytochrome and Differs from Rubber Oxygenase A (RoxA) in Its Biophysical Properties

Latex Clearing Protein (Lcp) of Streptomyces sp. Strain K30 Is a b -Type Cytochrome and Differs from Rubber Oxygenase A (RoxA) in Its Biophysical Properties

Comparative Studies on Rubber Biodegradation by Mixed Culture and Pure Culture Isolated From the Soil Samples

Recycling of Rubber

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