Bio-based anti-coagulant agent from microorganisms for natural rubber latex preservation

Natural rubber (NR) latex is whitish fluid derived from latex ducts which are in a layer outside the cambium of rubber trees (Hevea Brasiliensis). Latex is a stable dispersion of cis-1,4-polyisoprene rubber in an aqueous phase that contain non-rubber substances such as carbohydrates, proteins and amino acids and a range of enzymes. Non-rubber constitute in NR latex encourage the proliferation of bacteria that causes latex destabilization and coagulation due to their metabolism activities. Preserved NR latex is referred to latex that will not undergo coagulation process to form a solid natural rubber. Ammonia and others chemical-based preservative agent such as tetramethylthiuramdisulphite/ zinc oxide (TMTD/ZNO) have negative drawbacks to the environment and human health. The approach on searching for biological based format for NR latex preservation was due to the current focus on generating biologically processing system. Therefore, the objective of the present study is to search for biological based anti-coagulant agent for NR latex short-term preservation with antimicrobial and surfactant properties from microorganisms present in environment related with NR. A total of 28 isolates comprises 20 bacterial isolates and eight fungal isolates were successfully obtained from field NR latex, coagulated NR latex and soil from rubber plantation area. Screening for antimicrobial activity was performed using disc diffusion method. The surfactant activity was evaluated by measuring the surface tension of the extracts. The emulsification capability was determined by measuring the droplets size and distribution of oil in water emulsions. The field NR latex stability was characterized by means of bacterial population, volatile fatty acid numbers (VFA), and NR latex viscosity. Out of 28 isolates, only four isolates exhibited antimicrobial activity namely, Aspergillus fumigatus S14, A. flavus S16, Phaeomoniella chlamydospora EM19 and Bacillus amyloliquefaciens S10b. Meanwhile, in surfactant activity screening assay, only five isolates out of 28 isolates exhibited surfactant activity in which comprises of one fungi Lambdasporium sp. FS31 and four bacteria (Enterococcus feacalis F11, Myroides odoratus F5, Bacillus pumilus S1b and EM23). Microbial extracts from B. amyloliquefaciens S10b performed better than the other isolates that exhibited antimicrobial activity in acting as antimicrobial agent in field NR latex. Surfactant activities from Lambdasporium sp. FS31 showed greater potential to enhance the colloidal stability of the rubber particles. Out of the nine isolates, four isolates namely, P. chlamydospora EM19, B. amyloliquefaciens S10b, Lambdasporium sp. FS31 and M. odoratus F5 were prepared in a mixture. Field NR latex in the presence of microbial extracts from B. amyloliquefaciens S10b with Lambdasporium sp. FS31 showed less bacterial activity and slow increment of VFA number resulting in minimal changes of the NR latex viscosity indicated a good NR latex stability. In conclusion, this study showed that these microorganisms have potential to be used as an anti-coagulant agent for NR latex preservation

Experimental and computational study of latex clearing protein LcpK30 for rubber degradation

The demand for rubber products grows exponentially. This condition results in significant amounts of rubber waste in the environment. Most of the rubber waste would come from synthetic rubber. Rubber waste management without a sustainable strategy will harm the environment and the general public's health. This work aims to introduce a sustainable approach to degrading rubber using enzymes. Latex-clearing protein K30 (LcpK30) catalyses the oxidative cleavage of the C=C bond in cis-1,4-polyisoprene natural rubber (NR). This enzyme can degrade synthetic polyisoprene, but the degradation rate is still low, and its potential to degrade other diene rubbers remains poorly understood. The ability of LcpK30 to interact with a sizeable hydrophobic substrate is interesting. It thus raises the question of how the substrates can access the catalytic site that is buried inside the protein cavity. The work presented in this thesis explores ways to increase the applicability of LcpK30 to rubber degradation and provides a further understanding of how LcpK30 interacts with the polyisoprene substrate. Optimum production of the oligomers is essential to materialise the utilisation of the products from enzymatic degradation of NR for high-value applications. The optimum yield of oligomer at 65 % was obtained when the NR degradation was performed with 20 mg mL-1 NR emulsion at 30 °C and 6 µM LcpK30 added in three batches over 24 hours. Degradation of other diene rubbers with varied molecular weights, chemical structure and morphology catalysed by LcpK30 was assisted by pre-treating the rubber into film, particles and co-solvent emulsion. The degradability was evaluated based on the production of oligomers with carbonyl end-group. The oligomers were analysed using high performance liquid chromatography (HPLC), 1H Nuclear Magnetic Resonance (NMR) and gel permeation chromatography (GPC). It was found that the catalytic ability of LcpK30 to degrade other rubbers depended on the chemical structure and physical morphology of the rubber during the degradation. LcpK30 could degrade epoxidised NR with a low epoxide level (25 %), and the pretreatment improved LcpK30's contact with synthetic isoprene rubber (IR) molecules. The presence of other structural units (e.g. vinyl) in polybutadiene rubber or stereostructural changes (trans- polyisoprene) inhibits its catalytic activity. Protein tunnel identification using CAVER-Pymol plugin 3.0.3 revealed two dominant tunnels that could offer access to the substrate from the surface to the buried active site. Computational modelling of protein (LcpK30) and ligand (cis-1,4-polyisoprene with ten C=C bonds) interaction using GOLD molecular docking showed two potential binding modes for the substrate, which are in extended and folded conformation that mostly interacted with LcpK30 through hydrophobic contact. Intriguingly, this study provided insight into interactions taking place further away from the active site, which a short substrate model cannot fully explain. The potential site for introducing mutation that no studies have yet reported was identified, which were Ala159, Ile396, and Leu171. In this study, the Leu171Phe mutant was prepared and showed an improved heme occupancy with similar activity to the wild type. Findings from this study have enhanced the fundamental understanding needed to advance the research of LcpK30 to increase its potential as a biocatalyst for the environmentally friendly treatment of rubber waste. The application of LcpK30 can also be expanded as a tool for NR modification to develop new speciality rubber

Efficiency of commercial biological compounds as anticoagulant agents in natural rubber latex

This work studied the effect of streptomycin sulphate and surfactin on the stability of field natural rubber (NR) latex. Field NR latex was treated with streptomycin sulphate and surfactin in the absence and presence of ammonia. The stability of NR latex was determined by formation of volatile fatty acid (VFA), enumeration of the bacterial population, measurement of NR latex alkalinity and pH of the latex. Streptomycin sulphate caused significant reduction in bacterial population and VFA formation with an additional advantage as OH- ion stabiliser. Surfactin on the other hand was not suitable as NR latex preservative agent in the absence or presence of ammonia. Although instability of NR latex still appeared, combination of streptomycin sulphate and surfactin showed better control in terms of bacteria and VFA number compared to 0.3% ammoniated NR latex

Urban Savvy / Nor Faradina Johar ... [et al.]

The business venture proposed is named “Urban Savvy” in view of the nature of the business, which is on soft skills focusing in Professional Grooming Consultation Services. This business venture is joined by six partners who will each contribute different amount of capital in terms of cash and assets. Nature of the business is a consultancy services that focuses on a person’s professional image which covers communication and presentation skills, table manners and self-grooming. Professional outlook and work image is important for a person, especially to help appear competent and in control. This business is currently in high demand as first impressions and a professional image counts as one of the important factors to succeed nowadays. Our company is located in Subang Jaya in the resident area. The building or house is owned by our company’s Manager and it is used as an office by our company for as long as the Manager deems appropriate (with the agreement of other Partners). The target market of our company are the residents Kuala Lumpur and Selangor. These customers range from professionals to school leavers and undergraduates. Since the services offered are flexible in nature, customers are able to choose the service package that they want which suits their needs

Molecular cloning of partial and full length of human periostin gene into expression construct

Periostin which originally named as the osteoblast-specific factor 2 is highly homologous to jJigH3, a molecule induced by transfonning growth factor (TGF) -131; andfasciclin 1 an insect adhesion molecule. Penostin was proved to play an essential role in promoting the growth of tumor cells. Functional studies of human periostin should be perfonned to intensively understand the function and expression of periostin in nonnal and cancer tissues. In this report, cDNA fragments of periostin from human nonnal colon total RNA are isolated by R T -PCR for the purpose of amplification of the gene fragments, clone into pTargeT™ Mammalian Expression Vector System and sent to DNA sequencing analysis. Infonnation generated from DNA sequencing analysis is used to confinn the successful construction of the periostin into expression vector. Expression constructed ofperiostin into pTargeT™ vector can be used to begin functional studies of penostin inside mammalian cell lines system. The partial fragment of penostin gene with a predicted size of 685 bp was successfully amplified. However subcloned of periostin in pTargeTTM vector was unsuccessful due to several problems. Therefore, DNA sequencing analysis was not perfonn

Alternative anti-coagulant agents for natural rubber latex

Ammonia is the most favourable anti-coagulant agent for natural rubber (NR) latex preservation. Evolution of NR latex preservation via the chemical based format had always been the preferable alternative. However, with increased awareness regards to the impact of chemicals to the environment and the community, research is now directed towards finding an alternative to chemicals using biologically derived substances. An attractive alternative is by the microbial derived substance as a biological based format. Fungal extracts from Aspergillus sp. MRB25 performing equally well as field NR latex stabilized with ammonia and streptomycin sulphate. Hence, using the biological pathway to produce extracts from microorganisms as anti-coagulant agent for NR latex preservation revealed a promising outcome