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Prakash T, Yadav SR, Bürger M, Jendrossek D. Cleavage of natural rubber by rubber oxygenases in Gram-negative bacteria. Appl Microbiol Biotechnol 2024; 108:191. [PMID: 38305904 PMCID: PMC10837239 DOI: 10.1007/s00253-023-12940-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 12/06/2023] [Accepted: 12/14/2023] [Indexed: 02/03/2024]
Abstract
Bacterial degradation of natural rubber (NR) in an oxic environment is initiated by oxidative cleavage of double bonds in the NR-carbon backbone and is catalyzed by extracellular haem-containing rubber oxygenases. NR-cleavage products of sufficiently low molecular mass are taken up by the cells and metabolized for energy and biomass formation. Gram-negative and Gram-positive NR-degrading bacteria (usually) employ different types of rubber oxygenases such as RoxA and/or RoxB (most Gram-negative NR-degraders) or latex clearing protein Lcp (most Gram-positive NR-degraders). In order to find novel orthologues of Rox proteins, we have revisited databases and provide an update of Rox-like proteins. We describe the putative evolution of rubber oxygenases and confirm the presence of a third subgroup of Rox-related proteins (RoxCs), the biological function of which remains, however, unclear. We summarize the knowledge on the taxonomic position of Steroidobacter cummioxidans 35Y and related species. Comparison of genomic and biochemical features of strain 35Y with other species of the genus Steroidobacter suggests that strain 35Y represents a species of a novel genus for which the designation Aurantibaculum gen. nov. is proposed. A short summary on the capabilities of NR-degrading consortia, that could be superior in biotechnological applications compared to pure cultures, is also provided. KEY POINTS: • Three types of rubber oxygenases exist predominantly in Gram-negative microbes • S. cummioxidans 35Y contains RoxA and RoxB which are superior in activity • S. cummioxidans 35Y represents a species of a novel genus.
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Affiliation(s)
- Tulika Prakash
- School of Biosciences and Bioengineering, Indian Institute of Technology (IIT), Mandi, HP, 175005 , India.
| | - Sandhya R Yadav
- School of Biosciences and Bioengineering, Indian Institute of Technology (IIT), Mandi, HP, 175005 , India
| | - Marius Bürger
- Institute of Microbiology, University Stuttgart, Stuttgart, Germany
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Poly-cis-isoprene Degradation by Nocardia sp. BSTN01 Isolated from Industrial Waste. Appl Biochem Biotechnol 2022; 194:3333-3350. [PMID: 35286594 DOI: 10.1007/s12010-022-03854-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 02/11/2022] [Indexed: 11/02/2022]
Abstract
The natural and synthetic rubber (NR and SR) products are made up of poly-cis-isoprene which are estimated as one of the major solid-wastes and need to be cleared through bacterial bioremediation. The present research reports isolation and characterization of a gram-positive, non-spore forming, filamentous actinomycete Nocardia sp. BSTN01 from the waste of a rubber processing industry. We found NR- and SR-dependent growth of BSTN01 over a period of time. BSTN01 has been found to degrade NR by 55.3% and SR by 45.9% in 6 weeks. We have found an increase in the total protein of BSTN01 cells up to 623.6 and 573.9 µg/ml for NR and SR, respectively, after 6 weeks of growth in rubber-supplemented MSM medium. Scanning electron microscopy revealed adhesive growth of BSTN01 on the surface of NR and SR. Formation of aldehyde groups due to the degradation was indicated by Schiff's test and confirmed by FTIR-ATR analysis. The genome sequence of BSTN01 revealed the gene responsible for rubber degradation. The presence of lcp gene and structural analysis of the latex clearing protein further confirmed the reliability. Studies on quantification of rubber degradation capability by the isolated strain prove it to be an efficient degrader of NR and SR. This study revealed the genome sequence and structural analysis of the proteins responsible for degradation of rubber. A new fast-growing Nocardia strain can degrade both NR and SR with higher efficiency and have future potential for rubber solid-waste management either alone or in consortia.
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Basik AA, Sanglier JJ, Yeo CT, Sudesh K. Microbial Degradation of Rubber: Actinobacteria. Polymers (Basel) 2021; 13:polym13121989. [PMID: 34204568 PMCID: PMC8235351 DOI: 10.3390/polym13121989] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 06/04/2021] [Accepted: 06/07/2021] [Indexed: 01/25/2023] Open
Abstract
Rubber is an essential part of our daily lives with thousands of rubber-based products being made and used. Natural rubber undergoes chemical processes and structural modifications, while synthetic rubber, mainly synthetized from petroleum by-products are difficult to degrade safely and sustainably. The most prominent group of biological rubber degraders are Actinobacteria. Rubber degrading Actinobacteria contain rubber degrading genes or rubber oxygenase known as latex clearing protein (lcp). Rubber is a polymer consisting of isoprene, each containing one double bond. The degradation of rubber first takes place when lcp enzyme cleaves the isoprene double bond, breaking them down into the sole carbon and energy source to be utilized by the bacteria. Actinobacteria grow in diverse environments, and lcp gene containing strains have been detected from various sources including soil, water, human, animal, and plant samples. This review entails the occurrence, physiology, biochemistry, and molecular characteristics of Actinobacteria with respect to its rubber degrading ability, and discusses possible technological applications based on the activity of Actinobacteria for treating rubber waste in a more environmentally responsible manner.
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Affiliation(s)
- Ann Anni Basik
- Ecobiomaterial Research Laboratory, School of Biological Sciences, Universiti Sains Malaysia, Penang 11800, Malaysia;
- Sarawak Biodiversity Centre, Km. 20 Jalan Borneo Heights, Semengoh, Kuching, Sarawak 93250, Malaysia; (J.-J.S.); (C.T.Y.)
| | - Jean-Jacques Sanglier
- Sarawak Biodiversity Centre, Km. 20 Jalan Borneo Heights, Semengoh, Kuching, Sarawak 93250, Malaysia; (J.-J.S.); (C.T.Y.)
| | - Chia Tiong Yeo
- Sarawak Biodiversity Centre, Km. 20 Jalan Borneo Heights, Semengoh, Kuching, Sarawak 93250, Malaysia; (J.-J.S.); (C.T.Y.)
| | - Kumar Sudesh
- Ecobiomaterial Research Laboratory, School of Biological Sciences, Universiti Sains Malaysia, Penang 11800, Malaysia;
- Correspondence: ; Tel.: +60-4-6534367; Fax: +60-4-6565125
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Global Regulator of Rubber Degradation in Gordonia polyisoprenivorans VH2: Identification and Involvement in the Regulation Network. Appl Environ Microbiol 2020; 86:AEM.00774-20. [PMID: 32444473 DOI: 10.1128/aem.00774-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/17/2020] [Indexed: 12/29/2022] Open
Abstract
A cAMP receptor protein (CRPVH2) was detected as a global regulator in Gordonia polyisoprenivorans VH2 and was proposed to participate in the network regulating poly(cis-1,4-isoprene) degradation as a novel key regulator. CRPVH2 shares a sequence identity of 79% with GlxR, a well-studied global regulator of Corynebacterium glutamicum Furthermore, CRPVH2 and GlxR have a common oligomerization state and similar binding motifs, and thus most likely have similar functions as global regulators. Size exclusion chromatography of purified CRPVH2 confirmed the existence as a homodimer with a native molecular weight of 44.1 kDa in the presence of cAMP. CRPVH2 bound to the TGTGAN6TCACT motif within the 131-bp intergenic region of divergently oriented lcp1 VH2 and lcpR VH2, encoding a latex clearing protein and its putative repressor, respectively. DNase I footprinting assays revealed the exact operator size of CRPVH2 in the intergenic region (25 bp), which partly overlapped with the proposed promoters of lcpR VH2 and lcp1 VH2 Our findings indicate that CRPVH2 represses the expression of lcpR VH2 while simultaneously directly or indirectly activating the expression of lcp1 VH2 by binding the competing promoter regions. Furthermore, binding of CRPVH2 to upstream regions of additional putative enzymes of poly(cis-1,4-isoprene) degradation was verified in vitro. In silico analyses predicted 206 CRPVH2 binding sites comprising 244 genes associated with several functional categories, including carbon and peptide metabolism, stress response, etc. The gene expression regulation of several subordinated regulators substantiated the function of CRPVH2 as a global regulator. Moreover, we anticipate that the novel lcpR regulation mechanism by CRPs is widespread in other rubber-degrading actinomycetes.IMPORTANCE In order to develop efficient microbial recycling strategies for rubber waste materials, it is required that we understand the degradation pathway of the polymer and how it is regulated. However, only little is known about the transcriptional regulation of the rubber degradation pathway, which seems to be upregulated in the presence of the polymer. We identified a novel key regulator of rubber degradation (CRPVH2) that regulates several parts of the pathway in the potent rubber-degrader G. polyisoprenivorans VH2. Furthermore, we provide evidence for a widespread involvement of CRP regulators in the degradation of rubber in various other rubber-degrading actinomycetes. Thus, these novel insights into the regulation of rubber degradation are essential for developing efficient microbial degradation strategies for rubber waste materials by this group of actinomycetes.
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Gibu N, Arata T, Kuboki S, Linh DV, Fukuda M, Steinbüchel A, Kasai D. Characterization of the genes responsible for rubber degradation in Actinoplanes sp. strain OR16. Appl Microbiol Biotechnol 2020; 104:7367-7376. [PMID: 32681242 PMCID: PMC7413915 DOI: 10.1007/s00253-020-10700-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/19/2020] [Accepted: 05/24/2020] [Indexed: 10/25/2022]
Abstract
A Gram-positive rubber-degrading bacterium, Actinoplanes sp. strain OR16 (strain NBRC 114529), is able to grow on agar plates containing natural and synthetic rubber as the sole sources of carbon and energy. When this strain was grown on natural rubber latex overlay agar plates, translucent halos around the cells were observed. To identify the natural rubber degradation genes and other features of its metabolism, its complete genome sequence was determined. The genome of OR16 consists of 9,293,892 bp and comprises one circular chromosome (GenBank accession number AP019371.1) with a G + C content of 70.3%. The genome contains 8238 protein-coding and 18 rRNA genes. A homology search of the genome sequence revealed that three genes (lcp1, lcp2, and lcp3) are homologous to an extracellular latex-clearing protein (Lcp) of Streptomyces sp. K30. RT-PCR analysis revealed that lcp1 and lcp2 seem to constitute an operon. Purified lcp gene products have oxygen consumption activity toward natural rubber latex, suggesting that all these genes encode rubber-degrading enzymes in OR16. Quantitative reverse transcription-PCR analysis indicated that the transcription of these genes is induced during the growth of OR16 on natural rubber. The genes located adjacent to lcp1 and lcp3, which code for a TetR/AcrR-type transcriptional regulator, can bind to the promoter regions of these lcp genes. It is suggested that the putative regulators play a role in regulating the transcription of the lcp genes. These results strongly suggested that three lcp genes are required for the utilization of natural rubber in strain OR16. Key Points • The complete genome sequence of Actinoplanes sp. strain OR16 was determined. • Three lcp genes which are involved in the natural rubber degradation in OR16 were identified. • Transcription of these lcp genes is induced during utilization of rubber in OR16. • Two regulators, which bind to the promoter regions of lcp, were determined.
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Affiliation(s)
- Namiko Gibu
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan
| | - Tomoka Arata
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan
| | - Saya Kuboki
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan
| | - Dao Viet Linh
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan.,Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Masao Fukuda
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan.,Department of Biological Chemistry, Chubu University, Kasugai, Aichi, 487-8501, Japan
| | - Alexander Steinbüchel
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Münster, Germany.,Environmental Science Department, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Daisuke Kasai
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan.
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Kasai D. Poly( cis-1,4-isoprene)-cleavage enzymes from natural rubber-utilizing bacteria. Biosci Biotechnol Biochem 2020; 84:1089-1097. [PMID: 32114907 DOI: 10.1080/09168451.2020.1733927] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Natural rubber and synthetic poly(cis-1,4-isoprene) are used industrially in the world. Microbial utilization for the isoprene rubbers has been reported in gram-positive and gram-negative bacteria. Poly(cis-1,4-isoprene)-cleavage enzymes that are secreted by rubber-utilizing bacteria cleave the poly(cis-1,4-isoprene) chain to generate low-molecular-weight oligo(cis-1,4-isoprene) derivatives containing aldehyde and ketone groups. The resulting products are converted to the compounds including carboxyl groups, which could then be further catabolized through β-oxidation pathway. One of poly(cis-1,4-isoprene)-cleavage enzymes is latex-clearing protein (Lcp) that was found in gram-positive rubber degraders including Streptomyces, Gordonia, Rhodococcus, and Nocardia species. The other one is rubber oxygenase A and B (RoxA/RoxB) which have been identified from gram-negative rubber degraders such as Steroidobacter cummioxidans and Rhizobacter gummiphilus. Recently, the transcriptional regulation mechanisms for Lcp-coding genes in gram-positive bacteria have been characterized. Here, the current knowledge of genes and enzymes for the isoprene rubber catabolism were summarized.
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Affiliation(s)
- Daisuke Kasai
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Japan
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