Synthesis Of Natural Rubber Research Articles

TkJAZs-TkMYC2-TkSRPP/REF Regulates the Biosynthesis of Natural Rubber in Taraxacum kok-saghyz.

Taraxacum kok-saghyz (TKS) is a natural rubber (NR)-producing plant and a model plant for studying the biosynthesis of NR. Analyzing and studying the biosynthetic mechanism of NR is an important way to cultivate high-yield rubber TKS varieties. JAZ proteins, which belong to the Jasmonate ZIM domain family, function as negative regulators in the jasmonic acid (JA) signal transduction pathway. MYC2 is typically regarded as a regulatory factor for the target genes of JAZ proteins; JAZ proteins indirectly influence the gene expression regulated by MYC2 by modulating its activity. Theoretically, JAZ is expected to participate in growth, development, and responses to environmental cues related to rubber and biomass accumulation in TKS, all of which rely on the interaction between JAZ and MYC2. In this study, we identified 11 TkJAZs through homology searching of the TKS genomes and bioinformatics analyses. Subcellular localization, Y2H, and BiFC analysis demonstrate that TkJAZs and TkMYC2 are localized in the nucleus, with all TkJAZs and TkMYC2 showing nuclear colocalization interactions. Overexpression of TkMYC2 in TKS inhibited leaf development, promoted root growth, and simultaneously increased NR production. RNA-seq and qRT-PCR analysis revealed that the TkSRPP/REF genes exhibit varying degrees of upregulation compared to the wild type, upregulating the TkREF1 gene by 3.7-fold, suggesting that TkMYC2 regulates the synthesis of NR by modulating the TkSRPP/REF genes.

Synthesis and characterization of natural rubber/clay nanocomposite to develop electrical safety gloves

This research focuses on the synthesis of natural rubber (NR)/clay nanocomposites to develop electrical safety gloves. The mixture included sulfur as a cross-linked agent, dibenzothiazole disulfide (MBTS) as catalysis of the vulcanizing processes, zinc oxide (ZnO), and stearic acid (SA) as chemical activators to control the reaction. The manufacturing process of the sample compounds was developed to evaluate the optimal processing parameters. The main criteria were the formulation quantities, temperature conditions, curing time, mixing speed and mixing time. This method allowed the absence of lumps, bubbles or pores to evaluate the texture, color, strength, and elongation in the samples. Some samples simulate a finger form and size. The NR/clay nanocomposites were synthesized, with organo-clay reinforcements in 0.5, 1 and 2 wt% fractions. The nanocomposites were characterized by different methods. SEM was used to observe the morphology and distribution of the clay in the matrix. The NR crystallinity was accessed via XRD. The main functional groups of the nanocomposite were identified by FTIR spectroscopy, and DSC distinguished the glass transition temperature.

Comparative transcriptomics between high and low rubber producing Taraxacum kok-saghyz R. plants

BackgroundTaraxacum kok-saghyz R. (Tks) is a promising alternative species to Hevea brasiliensis for production of high quality natural rubber (NR). A comparative transcriptome analysis of plants with differential production of NR will contribute to elucidate which genes are involved in the synthesis, regulation and accumulation of this natural polymer and could help to develop Tks into a rubber crop.ResultsWe measured rubber content in the latex of 90 individual Tks plants from 9 accessions, observing a high degree of variability. We carried out de novo root transcriptome sequencing, assembly, annotation and comparison of gene expression of plants with the lower (LR plants) and the higher rubber content (HR plants). The transcriptome analysis also included one plant that did not expel latex, in principle depleted of latex transcripts. Moreover, the transcription of some genes well known to play a major role in rubber biosynthesis, was probed by qRT-PCR. Our analysis showed a high modulation of genes involved in the synthesis of NR between LR and HR plants, and evidenced that genes involved in sesquiterpenoids, monoterpenoids and phenylpropanoid biosynthesis are upregulated in LR plants.ConclusionsOur results show that a higher amount of rubber in the latex in HR plants is positively correlated with high expression levels of a number of genes directly involved in rubber synthesis showing that NR production is highly controlled at transcriptional level. On the other hand, lower amounts of rubber in LR plants is related with higher expression of genes involved in the synthesis of other secondary metabolites that, we hypothesize, may compete towards NR biosynthesis. This dataset represents a fundamental genomic resource for the study of Tks and the comprehension of the synthesis of NR and other biochemically and pharmacologically relevant compounds in the Taraxacum genus.

Development of novel on-line capillary gas chromatography-based analysis method for volatile organic compounds produced by aerobic fermentation

Many volatile compounds, such as isoprene, a precursor used in the synthesis of natural rubber, have been produced through fermentation using genetically engineered microorganisms. Despite this biotechnological success, measuring the concentrations of volatile compounds during fermentation is difficult because of their high volatility. In current systems, off-line analytical methods usually lead to product loss, whereas on-line methods raise the production cost due to the requirement of complex devices. Here, we developed a novel on-line gas chromatography (GC)-based system for analyzing the concentration of isoprene with the aim to minimize the cost and requirement for devices as compared to current strategies. In this system, a programmable logic controller is used to combine conventional GC with a syringe pump module (SPM) directly connected to the exhaust pipe of the fermentor, and isoprene-containing samples are continuously pumped from the SPM into the GC using an air cylinder recycle stream. We showed that this novel system enables isoprene analysis during fermentation with convenient equipment and without the requirement of an expensive desorption tube. Furthermore, this system may be extended to the detection of other volatile organic compounds in fermentation or chemical processes.

Synthesis of NR based Polyurethanes containing phosphorylated polymers as chain extenders

Natural Rubber (NR) based Polyurethanes (PU) with phosphorylated polymers as chain extenders were studied. Two types of polymers were investigated: poly-phosphonate and poly-phosphate synthesized using a RAFT methodology. Two molecular weights (5000 and 3000gmol−1) were targeted with dispersity close to 1.1. The PU films were prepared from a liquid Hydroxyl Telechelic Natural Rubber (HTNR) which was obtained through a controlled degradation. The mass percentage of the chain extenders added in the PU film was varied from 1 to 8%. The films were analysed using FTIR and Raman spectroscopy. A Raman mapping in particular was used to observe the phosphorus distribution in the PU film. In the case of the poly-phosphonate chain extender, the results highlighted that only with shorter chain lengths (n=13), a homogeneous distribution was observed.

Synthesis of NR‐g‐PMMA by “grafting from” method using ATRP process

AbstractGrafting poly(methyl methacrylate) or PMMA from natural rubber (NR) using ATRP process, NR has to be transformed into bromoalkyl‐functionalized NR (NRBr) acting as ATRP macroinitiator. The NRBr was prepared by two‐step chemical modification i.e., epoxidation and epoxide ring opening reaction using a nucleophile containing bromine atom such as 2‐bromopropionic acid (A1) and 2‐bromo‐2‐methylpropionic acid (A2). The fixation of A1 and A2 on 4‐methyl‐4‐octene, a model representing one repeat unit of NR, modified by epoxidation was prior studied and it was found that the resulting addition products from A2 using as ATRP initiator for MMA gave a better control of Mn,exp and low PDI of PMMA than that from A1. Then, the NR was transformed into ATRP rubber macroinitiator via epoxidation, followed by epoxide ring addition with only A2. 1H NMR was employed to determine the amount of A2 addition units on NR, which is considered to be the same amount of grafting sites for ATRP of MMA. The grafting of PMMA was then successfully carried out from the NR backbone by ATRP process. The PMMA grafts of the NR‐g‐PMMA were indeed linked to the NR backbone via ester linkage of the A2 unit. The PMMA grafts could be cleaved from the NR backbone by acid hydrolysis, while PMMA grafting by other conventional radical reaction could not be done. Then, the average MW of PMMA grafts after separation using acetone extraction was evaluated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011