Current Advances in Microbial Production of Acetoin and 2,3-Butanediol by Bacillus spp.

The growing need for industrial production of bio-based acetoin and 2,3-butanediol (2,3-BD) is due to both environmental concerns, and their widespread use in the food, pharmaceutical, and chemical industries. Acetoin is a common spice added to many foods, but also a valuable reagent in many chemical syntheses. Similarly, 2,3-BD is an indispensable chemical on the platform in the production of synthetic rubber, printing inks, perfumes, antifreeze, and fuel additives. This state-of-the-art review focuses on representatives of the genus Bacillus as prospective producers of acetoin and 2,3-BD. They have the following important advantages: non-pathogenic nature, unpretentiousness to growing conditions, and the ability to utilize a huge number of substrates (glucose, sucrose, starch, cellulose, and inulin hydrolysates), sugars from the composition of lignocellulose (cellobiose, mannose, galactose, xylose, and arabinose), as well as waste glycerol. In addition, these strains can be improved by genetic engineering, and are amenable to process optimization. Bacillus spp. are among the best acetoin producers. They also synthesize 2,3-BD in titer and yield comparable to those of the pathogenic producers. However, Bacillus spp. show relatively lower productivity, which can be increased in the course of challenging future research.

Butadiene Rubber in the Petrochemical Industry

The Butadiene is a raw material used in the petrochemical industry. The use of Butadiene has risen with petrochemical market growth. The Global market is forecasting a demand growth for butadiene applications, especially for rubber materials. The estimated synthetic rubber market is $19.1 billion in 2021 and forecasted to reach $23.2 billion in five years. The dynamic growth in butadiene applications will introduce new products used in many things from the food industry to sports and goods. Also, the rubber materials have different applications in the automotive industry, oil and gas, medical products, and plastics. Companies’ strategic planning to increase the production of synthetic rubber for the global market. The demand increased as new applications were introduced to the market. The stability of oil prices will have the rubber market steady which always leads to optimal pricing. The diver for Butadiene rubber applications is to maximize production by having different kind of materials that applied for several products. The global business development indicated the ability to increases the synthetic rubber market rubber and capacities, which will enhance the chemical process techniques, new technology design, and efficiency that will maximize production and minimize product cost. Looking into the price difference between synthetic and natural rubber, many fluctuation variables were introduced in the price of each type. For example, synthetic rubber price is high, depending on crude oil, natural gasoline and naphtha prices, since those feedstocks are fed to the cracking units, as C4 is one of the cracking products. Therefore, any change in the oil prices will influence the butadiene price, which is the feed for most rubber plants. In addition, the utilities required for those plants to operate have a major impact on overall price. On the other hand, Natural rubber is an agricultural product and dependent on soil type and weather.

Automation of data processing of the results of the chemical experiment on modeling the production of synthetic rubber using Microsoft Excel

The article presents an approach to the processing of chemical experiment’s data using a Microsoft Excel software. Instead of storing the experiment data in text files, it is proposed to use a Microsoft Excel file of a certain structure. A macro has been developed to automate the process of transferring data from text files to a common file. The described approach can be applied when solving problems accompanied by storing a large amount of statistical data, which can be obtained as a result of natural or computational experiments. The macro has been tested on the data of a laboratory and numerical experiment on the synthesis of a styrene-butadiene copolymer. This copolymer is formed as a result of carrying out the process of copolymerization in continuous mode in a cascade of continuous stirred tank reactors. The results of the experiment are the characteristics of the formed product for each reactor of the cascade at the end of each hour of process modeling. Transferring data into a single file of a certain structure allows you to graphically present the results of the experiment and facilitates further analysis of the characteristics of the product being studied, depending on the formulation and process conditions.

Mechanical and morphology characteristics of natural rubber-styrene butadiene rubber (NR-SBR) blends in the presence of natural microbentonite

Natural rubber (NR) has been the world renewable natural elastomer produced mainly in South East Asia from the sap of rubber tree (hevea brasiliensis). However it only exported to manufacturing countries for production of various engineering and specialty rubber products. Blending of the natural rubber with synthetic rubber such as styrene butadiene rubber (SBR) is a mean to improve engineering specification of the NR, especially due to exposure of mineral oils during its service life. Whereas natural microbentonite functions not only as filler but also as coagulant breaker in both SIR-10 and SBR matrices, which improves miscibility of the blends. In this work blending of Indonesian natural rubber (NR: SIR-10) with styrene butadiene rubber (SBR) were carried out in reflux reactor in xylene solution in the presence of various loading of natural microbentonite as fillers. Miscibility of the blends were measured from their mechanical properties as well as morphology of their fracture surfaces using electron microscopy (SEM). It was found that optimum loading of microbentonite in the NR/SBR (weight ratio: 50/50) blend was 3 per hundred rubber (phr), which showed good adhesion of the rubber matrices onto the filler surface and without any agglomeration.

Studies on Pyrolysis Oil derived from waste Tires as Fuel for Diesel Engine

In recent years, the number of automotive vehicles are increasing as these vehicles are becoming essential in developed and developing countries; which results in increase in waste tires. In most of the developing and under developed countries, the waste tires are not scientifically disposed and pollutes the environment. The synthetic rubber present in the tire is not biodegradable. Hence a research work is carried out to convert the waste tires and tubes into fuel using the process of pyrolysis. The tire pyrolysis oil (TPO) properties were compared with fossil diesel and it was observed that the properties of tire pyrolysis oil and diesel are closer. In the diesel engine the tire pyrolysis oil was used as partial substitute for the diesel and engine tests were performed by varying the engine loads. The results of the engine tests show that the tire pyrolysis oil can be effectively used as partial substitute in diesel engine with no need of making modifications in the engine’s fuel injection system. This paper discusses the waste tire statistics, conversion of tire into tire pyrolysis oil and engine studies with tire pyrolysis oil.

Ensuring energy efficiency of refrigeration piping

Improving energy efficiency and energy saving in refrigeration technology depends largely on the use of modern thermal insulation materials in the thermal insulation structures of refrigeration pipelines. The article presents a comparative analysis of the thermal characteristics and operational properties of heat-insulating materials used in refrigeration. The features of RUFLEX thermal insulation materials based on foamed synthetic rubber produced from domestic raw materials and their compliance with the requirements of energy efficiency, durability, operational reliability and safety are considered.

Bio-Based Polyisoprene Can Mitigate Climate Change and Deforestation in Expanding Rubber Production

Biomass is a promising renewable feedstock to produce polyisoprene for the rubber industry. Through metabolic engineering, sugars derived from pretreated and hydrolyzed cellulose and hemicellulose can be directly fermented to isoprene to produce rubber. Here we investigate the life cycle environmental impact of isoprene fermentation to produce bio-polyisoprene from agricultural residues (of Zea mays L.). Results show that the greenhouse gas (GHG) intensity of bio-polyisoprene (−4.59 kg CO2e kg−1) is significantly lower than that of natural rubber (Hevea brasiliensis) and synthetic rubber (−0.79 and 2.41 kg CO2e kg−1, respectively), while supporting a circular biogenic carbon economy. We found the land use intensity of bio-polyisoprene to be 0.25 ha metric ton−1, which is 84% lower than that from rubber tree plantations. We compare the direct fermentation to isoprene results with indirect fermentation to isoprene through the intermediate, methyl butyl ether, where dehydration to isoprene is required. The direct fermentation of isoprene reduces reaction steps and unit operations, an expected outcome when employing process intensification, but our results show additional energy conservation and reduced contribution to climate change. Among the ReCiPe life cycle environmental impact metrics evaluated, air emission related impacts are high for bio-polyisoprene compared to those for natural and synthetic rubber. Those impacts can be reduced with air emission controls during production. All other metrics showed an improvement for bio-polyisoprene compared to natural and synthetic rubber.

Influence of expiration date on detail reproduction of dental elastomers

Elastomers are synthetic rubber materials formed by polymers, which are joined by a small number of cross-links that form a three-dimensional network. The aim of the current study was to compare the surface detail reproduction of polyvinyl siloxane and polyether-based elastomeric impression materials (2 years after their expiration date) to the ones that have not exceeded this period-of-time. Four groups comprising 5 samples, each (n = 5), were divided based on material (polyvinyl siloxane – Express and polyether – Impregum Soft) and expiration date (expired, or not). The manipulated material was placed on a tray in a way to fully cover its inner part. Later on, it was placed on a metal matrix presenting 20-, 50- and 75-μm lines. Molds were removed after polymerization and surface detail reproduction was measured in comparator microscope (Stereozoom Microscope), along the 20 μm line (25 mm in length), at 4x-magnification, in compliance with ISO 4823. Surface detail reproduction values were subjected to descriptive analysis - results were expressed in percentage (%). All groups presented 100% of surface detail reproduction, regardless of impression material or expiration date. Surface detail reproduction of the investigated materials was not influenced by the evaluated elastomers’ expiration date.