Generation of Biodiesel and Carotenoids from Rhodotorula Glutinis using Sweet Sorghum Juice

The growth of Rhodotorula glutinis in sweet sorghum juice in three levels of three factors of temperature, carbon to nitrogen ratio and pH was evaluated. Accompanying of this growth was the generation of lipids converted to fatty acid methyl ester (FAMEs) and carotenoids. The optimized condition for maximum biomass and carotenoid accumulation was determined to be at 25C, pH of 5.5 and carbon to nitrogen ratio of 10. This condition yielded 22.7 g/L biomass with specific growth rate of 0.213 hr-1. At this condition the carotenoids generation was also maximum with 2.6 mg/gram biomass, comprising of torularhodin, beta-carotene and torulene. The accumulation of lipids following generation of biodiesel was highest at same temperature and pH but carbon to nitrogen ratio of 70, generating 96.3 mg of FAMEs/gram of biomass containing methyl ester of oleic acid, linoleic acid, palmitic acid, stearic acid and linolenic acid

Activated Sludge as Renewable Fuels and Oleochemicals Feedstock

The utilization of activated sludge as feedstock for biofuel and oleochemical production was investigated. Initial studies included optimization of biodiesel production from this feedstock through in situ transesterification. Results of these studies indicated that activated sludge biodiesel is not economically viable. This was primarily due to relatively low yields and the high economics of feedstock dewatering. Strategies to increase biofuel yield from activated sludge were then evaluated. Bacterial species present in activated sludge are known to produce a wide variety of lipidic compounds as carbon and energy storage material and as components of their cellular structures. In addition to lipidic compounds, activated sludge bacteria might also contain other compounds depending on wastewater characteristics. Among these bacterial compounds, only the saponifiable ones can be converted to biodiesel. The unsaponifiable compounds present in the activated sludge are also important, not only for biofuel production, but also for a wide variety of applications. Characterization of lipids in activated sludge revealed that it contains significant amount of polyhydroxyalkanoates, wax esters, acylglycerides and fatty acids. It also contains Template Created By: James Nail 2010 sterols, steryl esters and phospholipids as well as small but detectable amounts of hydrocarbons. This indicated that activated sludge could be also an inexpensive source of oleochemicals. Another strategy that was evaluated was lipid-enhancement by fermentation of activated sludge. Since the majority of products from petroleum oil are used as transportation fuel, the aim here was to increase the saponifiable lipids in activated sludge bacteria by applying a biochemical stimulus (i.e. high C:N ratio). Results showed that application of this stimulus increased the amount of saponifiable lipids, particularly triacyglycerides, in the activated sludge. Furthermore, fermentation homogenized the lipids in the sludge regardless of its source. This solidified the concept of utilizing wastewater treatment facilities as biorefineries. To support the utilization of other compounds in raw activated sludge for biofuel production, a model compound was chosen for catalytic cracking experiments. Results indicated that catalytic cracking of 1-octadecanol over H+ZSM5 proceeds via dehydration, producing octadecene. The octadecene then undergoes a series of reactions including β-C─C bond scission, alkylation, oligomerization, dehydrocyclization and aromatization producing aromatics, paraffins and olefins suitable for fuel applications

Analysis of Timbre in Melodic Arrangements of Popular Minang Songs Using a Spectrum Analyzer

Timbre is one of the main elements considered in musical arrangements, including contemporary Minang pop songs which have undergone significant development due to improvements in recording studio quality and increasingly qualified human resources. This study aims to describe the instrumentation and examine the characteristics of timbre in melodic instruments used in contemporary Minang pop song arrangements. Ableton Live 10 and Izotope Insight 2 software were used to analyze the audio spectrum produced by melodic instruments in recent Minang song arrangements. The results of audio processing using spectrum analyzer show that three main timbres of Minang songs are circulating and viral on social media: Acoustic Guitar, Bansi, and Overdrive Guitar. The first two instruments typically fill the melody line in the Intro, Interlude, and Coda, while the third instrument acts as a melody carrier in the transition part of the song. The instrumentation used in Minang song arrangements consists of acoustic instruments, specifically  Yamaha  guitars with Fishman Preamps, VST Instruments Sampletank2, and Real eight guitars. In this study, only two timbres were analyzed using the application: Acoustic Guitar and Bansi. The software analysis reveals that the two melodic timbres have unique characteristics formed by different overtone series formulas, with Acoustic Guitar having approximately 15 overtone pieces and Bansi having 8. Based on the results generated by the audio analysis application Izotope Insight 2, the timbre of guitar and bansi in contemporary Minang pop songs exhibit two unique characteristics. The guitar demonstrates a rich character with a significant number of overtone series at high frequencies. On the other hand, bansi tends to have a smooth and soft character due to its less dominant frequency points at each interval and lower amplitudes. Analisis Timbre pada Aransemen Melodik Lagu Minang Populer Menggunakan Spectrum Analyzer. Timbre merupakan salah satu elemen utama yang menjadi sorotan dalam menciptakan sebuah aransemen musik, begitupun dalam lagu pop Minang kontemporer yang telah mengalami perkembangan signifikan karena adanya peningkatan kualitas studio rekaman dan sumber daya manusia yang semakin berkualitas. Penelitian ini bertujuan untuk menggambarkan instrumen dan mengeksplorasi karakteristik timbre pada instrumen melodi yang digunakan dalam aransemen lagu pop Minang kontemporer. Penelitian ini menggunakan perangkat lunak Ableton Live 10 dan Izotope Insight 2 untuk menganalisis spektrum audio yang dihasilkan oleh instrumen melodi dalam aransemen lagu Minang terbaru. Hasil penelitian menunjukkan bahwa terdapat tiga timbre utama yang menjadi populer dalam lagu-lagu Minang masa kini yaitu: Gitar Akustik, Bansi, dan Gitar Overdrive. Dua instrumen pertama biasanya mengisi garis melodi pada Intro, Interlude, dan Coda, sedangkan instrumen ketiga berfungsi sebagai pembawa melodi pada bagian transisi lagu atau fill in. Instrumen yang digunakan dalam aransemen lagu Minang terdiri dari instrumen akustik berupa gitar dengan merk Yamaha dengan preamp Fishman, VST Instruments Sampletank2, dan gitar Real 8. Dalam penelitian ini, hanya dua timbre yang dianalisis menggunakan perangkat lunak yaitu: Gitar Akustik dan Bansi. Analisis perangkat lunak tersebut mengungkapkan bahwa dua timbre melodi memiliki karakteristik yang unik yang dibentuk oleh formula seri overtone yang berbeda, dengan Gitar Akustik memiliki sekitar 15 bagian overtone Series dan Bansi memiliki 8 Overtone Series. Berdasarkan sinyal audio yang dihasilkan oleh aplikasi, timbre melodi lagu Minang populer ditandai oleh gitar dengan warna  yang kaya dan Bansi dengan warna yang lembut dan halus. Selain itu, semua audio yang diperoleh dari sumber memiliki kualitas yang sangat baik.Timbre is one of the main elements considered in musical arrangements, including contemporary Minang pop songs which have undergone significant development due to improvements in recording studio quality and increasingly qualified human resources. This study aims to describe the instrumentation and examine the characteristics of timbre in melodic instruments used in contemporary Minang pop song arrangements. Ableton Live 10 and Izotope Insight 2 software were used to analyze the audio spectrum produced by melodic instruments in recent Minang song arrangements. The results of audio processing using spectrum analyzer show that three main timbres of Minang songs are circulating and viral on social media: Acoustic Guitar, Bansi, and Overdrive Guitar. The first two instruments typically fill the melody line in the Intro, Interlude, and Coda, while the third instrument acts as a melody carrier in the transition part of the song. The instrumentation used in Minang song arrangements consists of acoustic instruments, specifically  Yamaha  guitars with Fishman Preamps, VST Instruments Sampletank2, and Real eight guitars. In this study, only two timbres were analyzed using the application: Acoustic Guitar and Bansi. The software analysis reveals that the two melodic timbres have unique characteristics formed by different overtone series formulas, with Acoustic Guitar having approximately 15 overtone pieces and Bansi having 8. Based on the results generated by the audio analysis application Izotope Insight 2, the timbre of guitar and bansi in contemporary Minang pop songs exhibit two unique characteristics. The guitar demonstrates a rich character with a significant number of overtone series at high frequencies. On the other hand, bansi tends to have a smooth and soft character due to its less dominant frequency points at each interval and lower amplitudes

Salt-Induced Recovery of Volatile Organic Acids Using Non-Ionic Surfactants

Non-ionic surfactants are one of the most useful surfactants as they are the second largest group, produced by volume at about 35%. Due to their low toxicity, the demand for them is escalating due to an extensive use of these amphiphilic materials for an efficient, non-energy-requiring recovery of volatile organic acids (VOAs) from aqueous mixtures. This separation process is mainly due to the cloud point property of surfactants, which is referred to as the temperature of the system at which two phases are formed. One of the phases is micellar-rich and the other is micellar-poor. In these micelles, the surfactant molecules are oriented in such a way that the hydrophilic heads shield the hydrophobic tails from the other water molecules in the system. This assembly partitions the organic compounds within the interior of the micelles, which act as the pseudo-organic phase. This work elucidates how salting-out affects the cloud point of ethoxylated non-ionic surfactants, resulting in VOA separation. Studies suggest the sensitivity of the cloud point to the presence of electrolytes and its dependence on the parameters’ hydrophile–lipophile balance (HLB) and on the number of ethylene oxide (EON) units in the surfactant molecule. Electrolyte addition, in the form of salt, causes the dehydration of micelles as salt is a water-structure maker. The salt changes the solvent structure through aggregation and formation of larger micelles. This translates into a lipophilic shift, which reduces the cloud point and the surfactant’s HLB. As the HLB decreases, the more hydrophobic the surfactant becomes, resulting in better separation. The type of salt influences the characteristics of the interphase that separates the phases formed. Typically, polyvalent cations such as Al3+ and Ca2+ are more effective in decreasing the HLB than the monovalent cations (e.g., Na+ and K+) because of their higher surface charge densities. Since the surfactant’s HLB is dictated by its ethylene oxide component (i.e., HLB decreases with EON), it follows that non-ionic surfactants with a lower EON could achieve better separation in the presence of salt. Although the actual separation of VOAs could possibly be affected by other parameters (e.g., amount of added surfactant and salts and mass transfer rates), the response of surfactant’s properties (i.e., cloud point, HLB, and EON) to salt addition could be utilized to establish an enhanced VOAs extraction from aqueous systems

Adsorption kinetic modeling using pseudo-first order and pseudo-second order rate laws: A review

Adsorption for water and wastewater treatment has been the subject of many research in the scientific community, focusing mainly on either equilibrium or kinetic studies. Adsorption kinetics are commonly modeled using pseudo-first and pseudo-second order rate laws. Analyses of published works in the past two decades indicated that the pseudo-second order is considered to be the superior model as it can represent many adsorption systems. However, critical assessment of modeling techniques and practices suggests that its superiority could be a consequence of currently acceptable modeling norms which tend to favor the pseudo-second order model. The partiality was due to several modeling pitfalls that are often neglected. In addition, commonly used model validation tools are often used haphazardly and redundantly. As such, they cannot sufficiently provide any kind of certainty on the validity of a model. To eliminate modeling biasness, a new validation method was proposed and was then employed to re-examine previously published adsorption kinetic data

Using Self-Organizing Map Algorithm to Reveal Stabilities of Parameter Sensitivity Rankings in Microbial Kinetic Models: A Case for Microalgae

Microalgae are multi-purpose microbial agents due to their capability to efficiently sequester carbon dioxide and produce valuable biomass such as protein and single-cell oils. Formulation and tuning of microalgae kinetics models can significantly contribute to the successful design and operation of microalgae reactors. This work aimed to demonstrate the capability of self-organizing map (SOM) algorithm to elucidate the patterns of parameter rankings in microalgae models subject to stochastic variations of input forcing functions–bioprocess influent component concentration levels. These stochastic variations were implemented on a modeled chemostat with a deterministic microalgae kinetic model consists of ten time-dependent variables and eighteen model parameters. The methodology consists of two major stages: (1) global sensitivity analysis (GSA) on the importance of model parameters with stochastic sampling of bioreactor influent component concentrations, and (2) training of self-organizing maps on the datasets of model parameter rankings derived from the GSA indices. Results reveal that functional principal components analysis can project at least 99% of the time-dependent dynamic patterns of the model variables on B-splines basis functions. The component planes for hexagonal lattice SOMs reveal that the sensitivity rankings some parameters in the algae model tested can be stable over a wide range of variations in the levels of influent component concentrations. Therefore, SOM can be used to reveal the trends in multi-dimensional data arrays arising from the implementation of GSA of kinetic models under stochastic perturbation of input forcing functions

Evaluation of the Methane Production Potential of Catfish Processing Wastewater Using Various Anaerobic Digestion Strategies

The U.S. catfish industry is a major industry that has been declining over the years due to imports competition and growing operational costs. Catfish processing wastewater management and high energy requirement put a large financial burden on catfish processing facilities. Recovered protein-based solids have provided some value-added co-products, however, more co-products are needed to offset processing costs. Anaerobic digestion is a proven waste treatment method that produces methane, which is an energetic co-product that can be used within the processing facilities. This study was conducted to evaluate the potential of anaerobic digestion as an alternative to the currently used aerobic biotreatment of catfish processing wastewater. Initial assessments indicated the recalcitrance of the full-strength wastewater to anaerobic digestion, yielding only ~4 m3 per ton (U.S.) of input chemical oxygen demand (CODinput). Thus, several strategies were evaluated to improve the methane yield from the wastewater. These strategies include nutrient (nitrogen and sulfur) amendment, along with ozone, HCl, and NaOH pretreatment. The results showed that nutrient amendment was the most suitable strategy for improving the digestibility of the catfish processing wastewater. A methane yield of 121–236 m3/ton (U.S.) CODinput was obtained, with a purity of 67–80 vol.%. These results are similar to yields and purities of biogas from other feedstock, such as food waste, wastewater solids, and fish canning wastewater. This indicates that anaerobic digestion could be a viable alternative for simultaneous treatment and energetic co-product generation from catfish processing wastewater