Production of succinic acid via separate enzymatic hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) are alternatives and are environmentally friendly processes. These processes have attained considerable positions in the industry with their own share of challenges and problems. The high-value succinic acid is extensively used in chemical, food, pharmaceutical, leather and textile industries and can be efficiently produced via several methods. Previously, succinic acid production via chemical synthesis from petrochemical or refined sugar has been the focus of interest of most reviewers. However, these expensive substrates have been recently replaced by alternative sustainable raw materials such as lignocellulosic biomass, which is cheap and abundantly available. Thus, this review focuses on succinic acid production utilizing lignocellulosic material as a potential substrate for SSF and SHF. SSF is an economical single-step process which can be a substitute for SHF - a two-step process where biomass is hydrolyzed in the first step and fermented in the second step. SSF of lignocellulosic biomass under optimum temperature and pH conditions results in the controlled release of sugar and simultaneous conversion into succinic acid by specific microorganisms, reducing reaction time and costs and increasing productivity. In addition, main process parameters which influence SHF and SSF processes such as batch and fed-batch fermentation conditions using different microbial strains are discussed in detail.
Feather keratin is a biomass generated in excess from various livestock industries. With appropriate processing, it holds potential as a green source for degradable biopolymer that could potentially replace current fossil fuel based materials. Several processing methods have been developed, but the use of ultrasonication has not been explored. In this study, we focus on (i) comparing and optimizing the dissolution process of turkey feather keratin through sonication and conventional processes, and (ii) generating a biodegradable polymer material, as a value added product, from the dissolved keratin that could be used in packaging and other applications. Sonication of feather keratin in pure ionic liquids (ILs) and a mixture containing ILs and different co-solvents was conducted under different applied acoustic power levels. It was found that ultrasonic irradiation significantly improved the rate of dissolution of feather keratin as compared to the conventional method, from about 2 h to less than 20 min. The amount of ILs needed was also reduced by introducing a suitable co-solvent. The keratin was then regenerated, analyzed and characterized using various methods. This material holds the potential to be reused in various appliances.
Magnetic beads (AO-γ-Fe2O3) of alginate (A) impregnated with citrate coated maghemite nanoparticles (γ-Fe2O3) and oxidized multiwalled carbon nanotubes (OMWCNTs) were synthesized and used as adsorbent for the removal of methylene blue from water. The XRD analysis revealed that the diameter of γ-Fe2O3 is 10.24 nm. The mass saturation magnetization of AO-γ-Fe2O3 and γ-Fe2O3 were found to be 27.16 and 42.63 emu·g-1, respectively. The adsorption studies revealed that the data of MB isotherm were well fitted to the Freundlich model. The Langmuir isotherm model exhibited a maximum adsorption capacity of 905.5 mg·g-1. The adsorption was very dependent on initial concentration, adsorbent dose, and temperature. The beads exhibited high adsorption stability in large domain of pH (4-10). The thermodynamic parameters determined at 283, 293, 303, and 313 K revealed that the adsorption occurring was spontaneous and endothermic in nature. Adsorption kinetic data followed the intraparticle diffusion model. The AO-γ-Fe2O3 beads were used for six cycles without significant adsorptive performance loss. Therefore, the eco-friendly prepared AO-γ-Fe2O3 beads were considered as highly recyclable and efficient adsorbent for methylene blue as they can be easily separated from water after treatment.
Horse flies (Diptera: Tabanidae) are of medical and veterinary importance, as their blood-sucking feeding habit enables them to transmit several disease-causing agents. In Malaysia, the family Tabanidae consists of 120 species belonging to eight genera. The current study describes two new species (Chrysops idlani sp. nov. and Tabanus ekor sp. nov.) and presents new records for seven species: Tabanus fontinalisSchuurmans Stekhoven, 1926; Tabanus fuscifronsSchuurmans Stekhoven, 1926, Tabanus latifasciesSchuurmans Stekhoven, 1926, Tabanus megalops (Walker, 1854), Tabanus rhinargusPhilip, 1962, Tabanus salvazai (Surcouf, 1922), and Tabanus tristisWulp, 1881. Complete descriptions and illustrations are provided for the new species, and species variations for the new records are discussed. Male Tabanus latifasciesSchuurmans Stekhoven, 1926 and Tabanus perakiensis Ricardo, 1911 are thoroughly described herein.
SummarySchwannoma, a type of benign neurological tumour arising from Schwann cells, is commonly seen in the head and neck region. However, the incidence of cervical lymph node schwannoma is extremely rare, with only two cases reported in the literature. Schwannomatosis is a disease characterised by a constellation of multiple schwannomas seen in a patient, guided by at least one confirmational histological diagnosis. This is a case of a painless progressively enlarging submandibular swelling which is confirmed as a schwannoma based on histology. The patient is also diagnosed with schwannomatosis as the patient has multiple neurological tumours. Nodal schwannoma has a good prognosis and no documentation of recurrence in the literature. It may arise from sympathetic nerves located within the lymph node.
Pineapple (Ananas Comosus) is a tropical fruit having exceptional juiciness, vibrant tropical flavor and immense health benefits. Pineapples are not only taken fresh but they have been commercialized in the canning industry. Morris cultivar is mostly supplied to the canning industry where only the flesh is utilized and the rest of the pineapple (50 wt%) such as the core, stem, peels and crown are discarded as wastes. In the extraction of bromelain which is a vital proteolytic enzyme the whole pineapple including its peels, core, stem and crown can be utilized. This enzyme is very valuable and considered as a food supplement with a wide range of therapeutic benefits. Thus, in this study, bromelain is extracted from the flesh, crown, stem, core and peel of pineapples using simple one stage hollow fiber nanofiltration membrane process. The different parts of the pineapple were crushed to extract the juice. The juice was then centrifuged and the supernatant was then passed through a nanofiltration membrane. Results revealed the retentates from the different pineapple parts contain high amounts of bromelain in descending order flesh > peel > core > crown > stem. The amount of bromelain activity increased after every process especially after freeze drying.
The four heart valves represented in the mammalian hearts are responsible for maintaining unidirectional, non-hinder blood flow. The heart valve leaflets synchronically open and close approximately 4 million times a year and more than 3 billion times during the life. Valvular heart dysfunction is a significant cause of morbidity and mortality around the world. When one of the valves malfunctions, the medical choice is may be to replace the original valves with an artificial one. Currently, the mechanical and biological artificial valves are clinically used with some drawbacks. Tissue engineering heart valve concept represents a new technique to enhance the current model. In tissue engineering method, a three-dimensional scaffold is fabricated as the template for neo-tissue development. Appropriate cells are seeded to the matrix in vitro. Various approaches have been investigated either in scaffold biomaterials and fabrication techniques or cell source and cultivation methods. The available results of ongoing experiments indicate a promising future in this area (particularly in combination of bone marrow stem cells with synthetic scaffold), which can eliminate the need for lifelong anti-coagulation medication, durability and reoperation problems.
Magnetic nanofibers are composed of good dispersion of magnetic nanoparticles along an organic material. Magnetic nanofibers are potentially useful for composite reinforcement, bio-medical and tissue engineering. Nanofibers with the thinner diameter have to result in higher rigidity and tensile strength due to better alignments of lamellae along the fiber axis. In this study, the performance of electrospinning process was explained using response surface methodology (RSM) during fabrication of magnetic nanofibers using polyvinyl alcohol (PVA) as a shelter for (γ-Fe2O3) nanoparticles where the parameters investigated were flow rate, applied voltage, distance between needle and collector and collector rotating speed. The response variable was diameter distribution. The two parameters flow rate and applied voltage in primary evaluation were distinguished as significant factors. Central composite design was applied to optimize the variable of diameter distribution. Quadratic estimated model developed for diameter distribution indicated the optimum conditions to be flow rate of 0.25 ml/h at voltage of 45 kV while the distance and rotating speed are at 8 cm and 1500 rps respectively. The obtained model was verified successfully by the confirmation experiments.
In the study, the relationship between the quality and intensity of LED illumination with FAMEs produced were investigated. Nannochloropsis sp. was cultivated for 14 days under different intensities of 100, 150 and 200 μmol photons m(-2) s(-1) of red, blue and mixed red blue LED. The findings revealed that suitable combination of LED wavelengths and intensity; (red LED: 150, blue: 100 and mixed red blue: 200 μmol photons m(-2) s(-1)) produced maximum biomass growth and lipid content. It was observed that the quality and intensity of LED significantly influenced the composition of FAMEs. FAMEs produced under blue LED has high degree of unsaturation (DU) and low cetane number while those under red LED has low DU but higher CN. The combination of red blue LED has produced FAMEs with high ignition and lubricating property and also good oxidation stability indicated by the DU and CN values which lies midway between the red and blue.
In this study magnetic separable photocatalyst beads containing maghemite nanoparticles (γ-Fe(2)O(3)) in polyvinyl alcohol (PVA) polymer were prepared and used in the reduction of Cr(VI) to Cr(III) in an aqueous solution under sunlight. The unique superparamagnetic property of the photocatalyst contributed by the γ-Fe(2)O(3) and robust property of PVA polymer allow the magnetic beads to be recovered easily and reused for at least 7 times without washing. The concentration of γ-Fe(2)O(3) was varied from 8% (v/v) to 27% (v/v) and the results revealed that the beads with 8% (v/v) γ-Fe(2)O(3) exhibited the best performance where Cr(VI) was reduced to Cr(III) in only 30 min under sunlight. The use of the PVA has improved the bead properties and life cycle of beads which is in line with sustainable practices.
Many coagulants, mainly inorganic, are widely used in conventional water and wastewater treatment. Recent studies reported the occurrence of some chronic diseases associated with residual coagulant in treated wastewater. The use of alternative coagulants which are biodegradable and environmentally friendly could alleviate the problem associated with these diseases. This work investigates the capability of Jatropha curcas seed and presscake (the residue left after oil extraction) to reduce the turbidity of wastewater through coagulation. The coagulant was prepared by dissolving Jatropha curcas seed and presscake powder into solution. Then jar tests were conducted on kaolin solution as the model wastewater. The Jatropha seed was found to be an effective coagulant with more than 96% of turbidity removal at pH 1-3 and pH 11-12. The highest turbidity removal was recorded at pH 3 using a dosage of 120 mg/L. The flocs formed using Jatropha were observed to be bigger and to sediment faster when compared with flocs formed using alum. The turbidity removal was high (>98%) at all turbidities (100 NTU to 8000 NTU), suggesting its suitability for a wide range of industrial wastewater. The performance of Jatropha presscake after extraction of oil was also comparable to the fresh seed and alum at highly acidic and highly alkaline conditions. The addition of Jatropha did not significantly affect the pH of the kaolin samples after treatment and the sludge volume produced was less in comparison to alum. These results strongly support the use of Jatropha curcas seed and presscake as a potential coagulant agent.
Physical adsorption and photocatalytic reduction of Cr(VI) in magnetic separable beads were investigated. In order to elucidate the kinetics of photocatalytic process, operating parameters such as catalyst dosage and the initial concentration were examined in detail. It was observed that the reduction rate of Cr(VI) increased with an increase in the catalyst loading, as this translated into an increase in the number of available active sites. Critical scrutiny of the percentage of the initial reduction rate versus time at various initial concentration of Cr(VI) revealed that the rate of substrate conversion decreased as the initial concentration increased. The kinetic analysis of the photoreduction showed that the removal of Cr(VI) satisfactory obeyed the pseudo first-order kinetic according to the Langmuir-Hinshelwood (L-H) model and the absorption of Cr(VI) on the magnetic beads surfaces was the controlling step in the entire reduction process. Furthermore, desorption experiments by elution of the loaded gels with sodium hydroxide indicated that the magnetic photocatalyst beads could be reused without significant losses of their initial properties even after 3 adsorption-desorption cycles.
The rate of dye adsorption from aqueous effluents onto palm kernel shell (PKS) activated carbon has been studied experimentally using the batch adsorption method. The adsorption rates of methylene blue on PKS for systems of different initial dye concentrations are modeled using a film-pore-concentration dependent surface diffusion (FPCDSD) model. The FPCDSD model is sufficiently general and can be reduced easily to describe other simplified models. Using the FPCDSD model, only a single set of mass transfer parameters is required to describe the methylene blue/PKS system for different initial concentrations. A different set of mass transfer parameters are needed to obtain the best fitting if the pore diffusion is not included in the model.
The production and characterization of a bioflocculant, IH-7, by Aspergillus flavus was investigated. About 0.4 g of purified bioflocculant with an average molecular weight of 2.574 × 10(4)Da could be obtained from 1L of fermentation medium. The bioflocculant mainly consisted of protein (28.5%) and sugar (69.7%), including 40% of neutral sugar, 2.48% of uronic acid and 1.8% amino sugar. The neutral sugar components are sucrose, lactose, glucose, xylose, galactose, mannose and fructose at a molar ratio of 2.4:4.4:4.1:5.8:9.9:0.8:3.1. Fourier-transform infrared spectroscopy analysis revealed that purified IH-7 contained hydroxyl, amide, carboxyl and methoxyl groups. The elemental analysis of purified IH-7 showed that the weight fractions of the elements C, H, O, N and S were 29.9%, 4.8%, 34.7%, 3.3%, and 2.0%, respectively. IH-7 had good flocculating rate in kaolin suspension without cation addition and stable over wide range of pH and temperature.
The sweetpotato whitefly (WF), Bemisia tabaci, is a major pest that damages a wide range of vegetable crops in Malaysia. WF infestation is influenced by a variety of factors, including previous infestation of the host plant by other insect pests. This study investigated the effects of previous infestation of host chilli plants by the green peach aphid (Myzus persicae) on the olfactory behavioural response of B. tabaci, using free-choice bioassay with a Y-tube olfactometer. We analysed volatile organic compounds (VOCs) emitted by non-infested and M. persicae-infested chilli plants using solid-phase microextraction and gas chromatography-mass spectrometry. Our results showed that female WFs preferred non-infested to pre-infested plants. Collection and analysis of volatile compounds emitted by infested plants confirmed that there were significant increases in the production of monoterpenes (cymene; 1,8-cineole), sesquiterpenes (β-cadinene, α-copaene), and methyl salicylate (MeSA) compared to non-infested plants. Our results suggest that host plant infestation by aphids may induce production of secondary metabolites that deter B. tabaci from settling on its host plants. These results provide important information for understanding WF host selection and dispersal among crops, and also for manipulating WF behaviour to improve IPM in chilli.
Electrospinning is a simple and efficient process in producing nanofibers. To fabricate nanofibers made of a blend of two constituent materials, co-axial electrospinning method is an option. In this method, the constituent materials contained in separate barrels are simultaneously injected using two syringe nozzles arranged co-axially and the materials mix during the spraying process forming core and shell of the nanofibers. In this study, co-axial electrospinning method is used to fabricate nanofibers made of polyvinyl alcohol and maghemite (γ-Fe2O3). The concentration of polyvinyl alcohol and amount of maghemite nanoparticle loading were varied, at 5 and 10 w/v% and at 1-10 v/v%, respectively. The mechanical properties (strength and Young's modulus), porosity, and biocompatibility properties (contact angle and cell viability) of the electrospun mats were evaluated, with the same mats fabricated by regular single-nozzle electrospinning method as the control. The co-axial electrospinning method is able to fabricate the expected polyvinyl alcohol/maghemite nanofiber mats. It was noticed that the polyvinyl alcohol/maghemite electrospun mats have lower mechanical properties (i.e. strength and stiffness) and porosity, more hydrophilicity (i.e. lower contact angle), and similar cell viability compared to the mats fabricated by single-nozzle electrospinning method.
In this paper, both maghemite (γ-Fe2O3) and titanium oxide (TiO2) nanoparticles were synthesized and mixed in various ratios and embedded in PVA and alginate beads. Batch sorption experiments were applied for removal of barium ions from aqueous solution under sunlight using the beads. The process has been investigated as a function of pH, contact time, temperature, initial barium ion concentration and TiO2:γ-Fe2O3 ratios (1:10, 1:60 and 1). The recycling attributes of these beads were also considered. Furthermore, the results revealed that 99% of the Ba(II) was eliminated in 150min at pH 8 under sunlight. Also, the maghemite and titania PVA-alginate beads can be readily isolated from the aqueous solution after the process and reused for at least 7 times without significant losses of their initial properties. The reduction of Ba(II) with maghemite and titania PVA-alginate beads fitted the pseudo first order and second order Langmuir-Hinshelwood (L-H) kinetic model.
Bioconversion of higher strength of domestic wastewater biosolids (sludge) (4% w/w of TSS) by mixed fungal culture of Aspergillus niger and Penicillium corylophilum was studied in a laboratory. The effect of potential mixed fungi on domestic wastewater sludge accelerated the liquid state bioconversion (LSB) process. The highest production of dry sludge cake (biosolids) was enriched with fungal biomass to about 85.66 g/kg containing 25.23 g/kg of protein after 8 days of treatment. The results presented in this study revealed that the reduction of chemical oxygen demand (COD), total suspended solid (TSS), and specific resistance to filtration (SRF) of treated sludge were highly influenced by the fungal culture as compared to control (uninnoculated). The maximum removal rates in treated sludge (biosolids) supernatant recorded were 92% of COD and 98.8% of TSS. Lower SRF (1.08 x 10(12) m/kg) was perceived in microbially treated sludge after 6 days of fermentation. The observed parameters were highly influenced after 8 days of treatment. The influence of pH was also studied and presented in the paper.
A sludge lagoon has been adopted as a simple and cost effective method for dewatering of sludge. The processes occurring in a sludge lagoon include thickening, dewatering, storage and stabilization; all happening simultaneously. The objective of this study is to determine the dewatering and drying rates at pilot-scale which occur in a lagoon having different design configurations. Two types of sludge lagoons with different initial sludge depth (0.75 m and 0.375 m) were investigated to measure the drying behavior and drying efficiency. The first design is a sludge lagoon with a clay bottom where the dewatering mechanisms are decanting supernatant and evaporation. The second design is a sludge lagoon installed with a sand and underdrains system, where the dewatering mechanisms are filtration or draining and evaporation. Sludge drying kinetic models with high fitness were plotted to describe the sludge drying behavior. Drying of sludge in a sludge lagoon with a clay bottom can best be described by an exponential function. Whereas, drying of sludge in a sludge lagoon with sand and underdrains system followed a logarithmic function. A lagoon designed with sand and underdrains system and having shallower sludge depth was the most efficient. The reduction in volatile solids was lower than 4% during the study period. The drying process proceeded with an increase in dryness and decline in pH value.