A Novel Approach of Bioesters Synthesis through Different Technologies by Highlighting the Lowest Energetic Consumption One

Fatty acids esters have a wide application as bioplasticizers and biolubricants in different industries, obtained mainly in classic batch reactors, through an equilibrium complex reaction, that involves high temperatures, long reaction times, vigorously stirring, and much energy consumption. To overcome these shortcomings, we synthesized a series of fatty acid esters (soybean oil fatty acids being the acid components with various hydroxyl compounds) through novel low energy consumption technologies using a bubble column reactor, a microwave field reactor and for comparison meaning, a classic batch reactor. The obtained bioesters physicochemical properties were similar to one another, a good concordance among their rheological properties was obtained, but the energetic consumption is lower when using the bubble column or the microwave reactors instead of the classical batch reactor.

On the asymptotic stability of advection-diffusion equations of mass transport in a bubble column bioreactor

This study presents an asymptotic stability analysis of a model of a bioreactor converting carbon monoxide (CO) gas into ethanol through a C. autoethanogenum biocatalyst. The configuration is a bubble column reactor with co-current gas-liquid flows where gas feed is introduced by a gas distributor placed at the bottom of the column. A pure culture of C. autoethanogenum is subsequently injected at the bottom of the column; therein, cells are dispersed in the liquid and consume the dissolved gas and release by-products such as ethanol and acetic acid. Cellular growth and byproduct secretion are affected by spatially varying dissolved gas concentrations due to advection-diffusion mass transports which are induced by the effect of the injection pressure and gravitational force. The model accounts for four species representing the biomass, the CO substrate in the liquid phase, and two by-products - ethanol and acetic acid. Substrate dynamics is described by an advection-diffusion equation. We investigate the asymptotic stability of the biomass dynamics that is a requirement for the system’s controllability, i.e. for the possibility to steer a dynamical system from an arbitrary initial state to an arbitrary final state using a set of controls. The concept of stability of the controls is extremely relevant to controllability since almost every workable control system is designed to be stable. If a control system is not stable, it is usually of no use in practice in industrial processes. In the case of a bioreactor, the control is the biomass and controllability is the possibility of modulating through this control the ethanol production. We present a test for asymptotic stability, based on the analysis of the properties of the dynamic function defining its role as storage function.

Remediation of oil-drilling cuttings by ozonation in semibatch bubble column reactors

The remediation of oil-drilling cuttings (ODC), containing a high percentage of total organic carbon (TOC), total petroleum hydrocarbons (TPH) and moisture, is a challenge. Ozonation is an advanced oxidation method able to destruct a broad variety of organic substances from water and soil. Oil-drilling cuttings are pre-treated inside a sonication bath with three solutions of artificial seawater containing 0.0, 0.2, and 0.5% w/w sodium dodecyl sulphate (SDS) which acts as surfactant and favours the solubilisation of hydrocarbons from the solid to the liquid phase. Afterwards, each pre-treated ODC is diluted at a ratio 1:5 with the corresponding type of seawater, and ozonation of the suspension occurs in a bubble column reactor made of poly methyl methacrylate (PMMA). The transient changes of the TOC content in ODC during the various stages of its treatment are measured with the Walkley-Black titration method. It seems that a percentage ~12-25% of TOC dissolves and is transferred from ODC to seawater, while the treatment of ODC suspended in seawater with ozone leads to the complete removal of the TOC after 2 hrs.

CHEMICAL DEPOLYMERIZATION OF WASTE PLASTICS IN BUBBLE COLIUMN REACTOR FOR BLENDED FABRICATION

The degradation of waste plastics in the environment is such an essential issue for Earth protection. This study indicated the importance of using waste bottles to produce recycled depolymerization Polyethylene Terephthalate (DPET). The bubble column reactor technique and its effect in the depolymerization process have been investigated. The DPET with Poly-methyl methacrylate (PMMA) has been used to fabricate the hybrid polymer to improve the mechanical properties. Thus, different percentages (1, 2, 3, 5, and 10 %) of (DPET) are used to surmise its repercussions on the mechanical properties of the polymer. These ramifications were studied through a sequence of research laboratory tests, including tensile strength, Charpy impact, and shore-D hardness, and Fourier Transform Infrared Spectroscopy (FTIR) analysis. The results show a development interest, especially for impact strength and surface hardness, where both tests show compatible results, especially at (10%) of DPET. At the same time, maximum results of tensile strength are at (3%). FTIR analysis shows a chemical reaction between DPET and PMMA, which significantly improves the characteristics and makes it a wide range of available applications.

Simultaneously Recovery of Phosphorus and Potassium Using Bubble Column Reactor as Struvite-K and Implementation on Crop Growth

Struvite-K, similar to NH4-struvite with a composition of Mg:K:P (1:1:1). It is called struvite-K because the K replaces the NH4 in struvite. The composition usually used as fertilizer and can be recycling from wastewater including livestock wastewaters. In addition, Struvite-K which tends to form scale on surfaces of equipment which problem in many industries. The present study was used bubble column reactor which simple and efficient. In addition, the process can be implementation in wastewater industry which low-tech processes. Then, the struvite-K precipitate was implementation on crop growth which compared with coffee husk compost. The results show the removal of P via struvite-K showed 98.5% with the precipitation Mg:P of 0.7 and K:P of 1 with yields of 11.28 gram. Increases of magnesium dosage which decreases of P removal rate and affected of crystal size structure. Compost and struvite-K have similar positive impact on crop growth of (radish and komatsuna) were compared than control. In the other hand, the struvite-K is more effective than compost. This might be indicated that struvite-K is more slow-release nutrient than compost and higher macro nutrient supplied on soil which crop needed.

Batch and Fed-Batch Production of β-carotene by Rhodotorula Toruloides KP324973 Using Corn Steep Liquor As Sole Carbon Source

Application of agro-industrial waste in microbial fermentation is interesting in economic and environmental aspects. Carotenoids production by Rhodotorula toruloides KP324973 was investigated using corn steep liquor (CSL) as sole carbon source. Haldane model with constants µmax = 0.056 h-1, KS = 1.54 vv-1%, and KI = 58.58 vv-1% showed best describe of cell growth kinetics on CLS. A same maximum carotenoid production rate (Rp) about 2.23 μg gcell-1 h-1 was obtained at initial CSL concentration of 5 v/v% after 72 h and 21 h in batch cultivation in shaken flasks and bubble column reactor (BCR), respectively. Further improvement of carotenogenesis was followed by fed-batch cultivation in BCR where the optimal setting of factors at feed flow rate of 5 mL h-1, pH of 5.66, and temperature 14 ˚C gained a highest Rp = 8.686 μg gcell-1 h-1. Chromatographic analysis showed more than 94% of produced carotenes was β-carotene.