Salt Medium Research Articles

The impact of concentration on the biotreatment of hair relaxers using Hydrocarbonoclastic Pseudomonas and Mucor Species from Ezu River, Awka, Nigeria

The contamination of an aquatic environment by hydrocarbons and other noxious compounds due to human activities may cause toxicity to microorganisms and may stimulate microbial activity especially at low concentrations while their persistence can be detrimental to the entire ecosystem. It is crucial therefore, to assess the risks of these pollutants for environmental policy. Diesel was used as carbon source in mineral salts medium for the isolation of petroleum degrading microorganisms from Ezu River using vapor transfer technique. Plates were incubated at 37 0C and 28 0C for bacterial and fungal cultures, respectively. Of the 23 bacterial and 4 fungal isolates recovered, Mucor species and Pseudomonas aeruginosa were the best hydrocarbon utilizing isolates obtained. The isolates were assessed for their ability to utilize both lye-containing and lye-free hair relaxers at different concentrations (0.2 – 1% w/v) in mineral salts medium for 14 days. The optical density (OD660nm), the biochemical oxygen demand (BOD5), chemical oxygen demand (COD), and pH of the medium were monitored during incubation. The toxicity of the hair relaxers to Nitrobacter sp. was also assessed. Results showed that Pseudomonas aeruginosa utilized both lye-free(Lf) and lye-containing (Lc)hair relaxers at all concentrations as indicated by the high colony counts, reduction in BOD5 and COD during the incubation period. Mucor sp. grew better on higher concentrations Lc hair relaxer (1%> 0.8%> 0.6% w/v), but with minimal growth at lower concentrations of same relaxer (0.2%< 0.4%< 0.6% w/v). On the contrary, lye-free hair relaxer supported heavy growth of Mucor sp. at all concentrations tested. The growth of Nitrobacter sp. got inhibited by both types of hair relaxers between concentrations 0.6 and 1% w/v, with moderate growth at lower concentrations (0.2 – 0.4% w/v). The toxicity outcome of these hair relaxers to Nitrobacter species implies that the indiscriminate discharge of hair-relaxer-containing salon wastewater into the soil may affect the biogeochemical activities of the soil microbial communities. In addition, Pseudomonas aeruginosa and Mucor species recovered in this study can be used to attenuate sites contaminated by hair salon wastewater.

Identification and Screening of Biosurfactant Producing Bacteria from Mechanic Workshops Soil in Gusau Metropolis, Nigeria

Biosurfactants are molecules that reduce interfacial tension. Their chemical composition can vary widely, but they have in common their amphiphilic or amphipatic nature and can thus be soluble in aqueous as well as in organic solvents. The study was carried out to identify and screen biosurfactant producing bacteria from mechanic workshops in Gusau metropolis. Eight (8) soil samples were collected at the depth of 0-7 and 8-15cm from selected mechanic workshops located at Gada Biyu, Taqama bye-pass, Birnin Ruwa and non-oil contaminated soil as control for analysis. The physicochemical parameters were analysed using standard procedures (blood heamolysis, drop collapse, oil displacement and emulsification index) methods were used to screen biosurfactant production by the isolates. Mineral salt medium supplemented with 1% Actual gasoline oil (AGO) as sole sources of carbon was used to isolate hydrocarbon degrading bacteria, while heterotrophic bacteria were isolated using nutrient Agar. The soil samples from the study area were characterised with smooth, grey to dark brown soil with an unpleasant smell as well as as well as high temperature and pH. The three mechanic workshops used for this study, shows relatively higher counts for Hydrocarbon Degrading Bacteria while higher heterotrophic bacterial count was obtained from the control site though there was no significant difference between individual mechanic workshop (p>0.05). The isolates are potential biosurfactant producers based on their performance especially blood haemolysis and emulsification index. The isolates identified belonged to the species of Bacillus, Pseudomonas, Acinetobacter, Micrococcus and Serratia.

Impact of biosurfactant produced by Bacillus spp. on biodegradation efficiency of crude oil and anthracene

Biosurfactants are surface active molecules generated by various microorganisms, including bacteria, actinobacteria, algae, and fungi. In this study, bacterial strains are isolated from soil contaminated with used motor oil and examined for potential biosurfactant production. A minimum salt medium (MSM), with crude oil as the only carbon source, is used to isolate potential biosurfactant-producing bacterial strains. About 23 strains are isolated, and all are subjected to the primary screening methods for biosurfactant production. Based on the emulsification index, oil displacement, and drop collapse screening methods, two isolates with potential biosurfactant-producing ability are selected for further studies. The synthesis of biosurfactants, crude oil and anthracene biodegradation is carried out with strains DTS1 and DTS2. Both strains show significant outcomes in crude oil degradation. In addition, both strains can utilize anthracene as the sole carbon source. During the degradation course, changes in the growth conditions are continuously monitored by measuring turbidity and pH. In this degradation study, the biosurfactant production aptitude of the isolated strains plays an essential role in increasing the bioavailability of hydrophobic hydrocarbons. These strains are identified down to the molecular level by employing 16S rRNA gene sequencing, and the acquired sequences are submitted to get the accession numbers. These prospective strains can be utilized to remediate hydrocarbon-contaminated environments.

Atrazine Degradation by Bacillus safensis Strain BUK_BCH_BTE6 Isolated from Agricultural Land in Northwestern Nigeria

Atrazine herbicide is known to disrupt the endocrine system and is potentially carcinogenic. Consumption of which is devastating. This research aimed to isolate and characterize bacteria with atrazine degrading ability. An enrichment method was adopted to isolate the bacteria on mineral salt media following serial dilution. The isolate was identified molecularly and characterized based on effects of temperature, pH, substrate concentration, incubation time, inoculum size and heavy metals. GC-MS analysis was performed to identify the metabolites and degradation efficiency. The isolate was identified as Bacillus safensis strain BUKˍBCHˍBTE6 based on 16S rRNA gene sequence and molecular phylogenetic analysis. Growth and degradation of atrazine by this bacterium was optimal at 35 °C, pH of 7.5, 400 mgL-1, inoculum size 600 µL after 48 h. The growth of the isolate was inhibited by 2 ppm Hg, Cd, Cr, Pb, Ar and Ni. The degradation efficiency after 120 h was 88.85%. GC-MS analysis detected the formation of Desethyldeisopropylatrazine, Deisopropylatrazine, N-Ethylammelide and Cyanuric acid as metabolites. This isolate can be efficient atrazine degrader, hence may be beneficial for bioremediation of atrazine polluted sites.

Aggregation phenomena and physico-chemical properties of tetradecyltrimethylammonium bromide and protein (bovine serum albumin) mixture: Influence of electrolytes and temperature

It is important for biological, pharmaceutical, and cosmetic industries to understand how proteins and surfactants interact. Herein, the interaction of bovine serum albumin (BSA) with tetradecyltrimethylammonium bromide (TTAB) in different inorganic salts (KCl, K2SO4, K3PO4.H2O) has been explored through the conductivity measurement method at different temperatures (300.55 to 325.55 K) with a specific salt concentration and at a fixed temperature (310.55 K) using different salts concentrations. The extent of micelle ionization (α) and different thermodynamic parameters associated with BSA and TTAB mixtures in salt solutions were calculated. Evaluation of the magnitudes of ∆Hm0 and ∆Sm0 showed that the association was exothermic and primarily an enthalpy-operated process in all cases at lower contents of BSA, but the system became endothermic, and entropy driven in the presence of K3PO4.H2O at a relatively higher concentration of BSA. The enthalpy–entropy compensation variables were determined, which explained the types and nature of interactions between TTAB and BSA in salt media. Molecular docking analysis revealed that the main stabilizing factors in the BSA-TTAB complex are electrostatic and hydrophobic interactions. These findings aligned with the significant results obtained from the conductometry method regarding the nature and characteristics of binding forces observed between BSA and TTAB.

BIODEGRADATION OF GLYPHOSATE CONTAINING HERBICIDE BY SOIL FUNGI

Ten fungal isolates were isolated from two herbicide-contaminated soil farms obtained from Amoyo and the University of Ilorin environment in Kwara State after enrichment with mineral salt medium (MSM) supplemented with glyphosate-containing herbicide. The growth of fungal isolates was efficiently stimulated by the organophosphorus herbicide. Fungi isolated were subjected to screening by varying the herbicide concentrations from 0.1 to 3%, which is prepared with MSM. This screening showed that all the fungal isolates had the ability to act in the biodegradation process. However, varying degradative potentials were observed, as some had heavy growth while others had only slight or no growth as the concentrations of the herbicide increased. The ten fungal isolates were characterized and identified as Aspergillus niger, Penicillum spinulosum, Aspergillus terrus, Aspergillus flavus, Fusarium oxysporum, Mucor spp., Aspergillus oryzae, Aspergillus tamari, Rhizopus stolonifer, and Trichoderma koningii, and these were reduced to six after screening with 3% concentration of the herbicide. Four isolates (A. niger, F. oxysporum, Mucor spp., and A. flavus) were selected based on their growth ability on the medium during screening and were used in the biodegradation study. However, there is an increase in fungal dry weights ranging from 8.60 to 18% for 12 days. This shows that these fungi can be employed in the biodegradation of herbicides since they are potentially effective species and are environmentally safer alternative to protect the soil from the contamination of glyphosate-containing herbicide residues.

Bioplastic (Polyhydroxyalkanoate) producing Indigenous Bacteria from Agricultural Soil Samples

Polyhydroxyalkanoate (PHA) is the naturally occurring biopolymer produced by the microorganisms. It is biodegradable and having physicochemical properties similar to conventional synthetic plastics and it can be used as an alternative to plastics. PHA is produced by microorganisms including bacteria, archaea and fungi. It gets accumulated inside the microorganisms as crystal in the presence of excess source of carbon, nitrogen, sulphur, oxygen and limited source of other nutrients. In this study PHA producing strain was isolated from agricultural soil sample. All the isolates obtained were screened for PHA production by using Nile red and Sudan black dyes. The potential isolate was characterized by biochemical tests and identified using 16S rRNA sequencing. The isolate showed sequence similarity with Priestia aryabhattai B8W22 and was designated as Priestia aryabhattai VITJK01. For PHA production, seed culture was prepared and inoculated in mineral salt medium containing glucose as a carbon source. PHA was extracted from cell dry weight biomass using methanolysis. It produced polyhydroxybutyrate (PHB) compounds including dodecane, penta decanoic acid, octadecanoic acid and heptadecanoic acid identified by Gas Chromatography Mass Spectrometry. Based on the results, it can be concluded that Priestia aryabhattai VITJK01 is a potential source for PHA/PHB production.

Purification and characterization of catechol 1,2-dioxygenase (EC 1.13.11.1; catechol-oxygen 1,2-oxidoreductase; C12O) using the local isolate of phenol-degrading Pseudomonas putida.

The purpose of the present study was to purify and characterize the catechol 1,2-dioxygenase (EC 1.13.11.1; catechol-oxygen 1,2-oxidoreductase; C12O) enzyme from the local isolate of Pseudomonas putida. This enzyme catalyzes the initial reaction in the ortho-pathway for phenol degradation in various gram-negative bacteria, including the genus of Pseudomonas. Pseudomonads are commonly used in the biodegradation of xenobiotics due to their versatility in degrading a wide range of chemical compounds. Eighty-nine soil samples were taken from the contaminated soil of the Midland Refineries Company (MRC) of Al-Daura refinery area at Baghdad from April to August 2021. The samples were grown in a mineral salt medium containing 250mg per L of phenol to test their ability to biodegrade phenol. The pH was adjusted to 8.0 at 30°C using a shaking incubator for 24-48h. A number of 62 (69.6%) isolates of the total number were able to degrade phenol efficiently. The findings of the VITEK system and the housekeeping gene 16S rDNA confirmed that out of the positive isolates for phenol degradation, 36 from 62 (58.06%) were identified as Pseudomonas spp. isolates. Those isolates were distributed as P. aeruginosa 30 (83.3%) and P. putida 6 (16.6%). The enzyme production capabilities of the isolates were evaluated, and the highest activity was 2.39 U per mg for the isolate No. 15 which it was identified as P. putida. The previous isolate was selected for enzyme production, purification, and characterization. The enzyme was purified using ion exchange and gel filtration chromatography, with a combined yield of 36.12% and purification fold of 15.42 folds. Using a gel filtration column, the enzyme's molar mass was calculated to be 69kDa after purification. The purified enzyme was stable at 35°C and a pH of 6.0.

Recent progress in melt pyrolysis: Fabrication and applications of high‐value carbon materials from abundant sources

AbstractThe escalating demand for sophisticated carbon products, including carbon black, carbon nanotubes (CNTs), and graphene, has yet to be adequately addressed by conventional techniques with respect to large‐scale, efficient, and controllable carbon material synthesis. Molten pyrolysis emerges as a propitious strategy for generating such high‐value carbon materials. Abundant carbon sources encompassing methane (CH4), carbon dioxide (CO2), biomass, and plastics can undergo thermal decomposition into carbon constituents within molten metal or salt media. This methodology not only obviates dependence on traditional fossil fuels but additionally enables modulation of carbon material morphologies by varying the molten media, thereby presenting substantial potential for effective and controlled carbon material fabrication. In this review, we examine the capacity of molten pyrolysis in producing high‐value carbon materials derived from CH4, CO2, biomass, and plastics. Concurrently, we present a detailed overview of the potential applications of this novel methodology, particularly emphasizing its relevance in the fields of supercapacitors, flexible materials, and electrochemical cells. Furthermore, we contemplate future trajectories for molten pyrolysis, accentuating that amalgamation with auxiliary processes or technologies—like renewable energy systems and carbon capture and storage—represents a remarkably promising route for continued investigation.

Isolation and Characterization of Phenol degrading Bacteria from Wastewater

Out of 30 bacterial isolates from wastewater were checked for growth on a minimal salt medium amended with different concentrations of phenol by flask culture technique. The eight most tolerant bacterial strains to the higher concentrations of phenol, designated as W2, W5, W9, W12, W14, W15, W19 and W29, were investigated for their ability to grow and degrade phenol. Among the eight higher phenol degrading isolates, W15 can tolerate up to 1000 ppm of phenol concentrations and grow and degrade 94% of phenol within 72 hrs. The optimum temperature and pH condition were 37C◦ and 7, respectively. The yeast extract is the best organic nitrogen source, while ammonium chloride is the best inorganic nitrogen source for the growth and degradation of phenol.

Kinetics of biodesulfurization of South African diesel using Pseudomonas aeruginosa

As a result of several environmental and health challenges associated with the emission of SOx during the direct combustion of diesel, stringent regulations have been issued by the Environmental Protection Agency (EPA) and the South African government to all refineries in South Africa. Therefore, the development of an effective, affordable, and less energy-intensive technique is therefore urgently required. In this recent study, real South African diesel (obtained after HDS, 120 ppm) was degraded by resting cells of Pseudomonas aeruginosa in a batch experiment. About 5 mL of diesel was measured into a 250 mL Erlenmeyer flask with 5 mL of resting cell in glycerol/NaCl (1:1) and 20 mL of Basal Salt Media (BSM). The mixture was incubated for 8 h, at 37 °C, and agitated at 130 rpm, with an initial hydrodesulfurized diesel concentration of 120 mg/L and cell mass of 1.2 gDCW/L. High-Liquid Chromatography and Gas/Mass (GC/MS) chromatography were used to determine the initial and final concentrations of the synthetic and real diesel samples. Findings showed about 70.54 % removal of DBT in 120 ppm desulfurized diesel. Meanwhile, Pseudomonas aeruginosa selectively converted sulfur atoms in DBT compound to 2-HBP. Michaelis-Menten for modeling the growth of the bacteria fitted well into the experimental data. Similarly, First-order kinetic fitted and described well the behavior of the bacteria for degradation of DBT in synthetic and real diesel samples. The findings of this investigation indicated that biodesulfurization would be a more effective method to complement the hydrodesulfurization (HDS) technique as opposed to the primary methods for desulfurizing organo-sulfur compounds in diesel oil. This will assist the refineries to meet up with the stringent regulation to minimize the emission of sulfur compounds, which cause environmental pollution and health problems in South Africa and all over the world.

The micellization of tetradecyltrimethylammonium bromide and cefixime trihydrate mixture: investigation of the effects of sodium-based electrolytes and temperatures on the physico-chemical parameters and interaction forces

ABSTRACT This study exposes the influence of sodium electrolytes and temperature on the interaction forces between tetradecyltrimethylammonium bromide (TTAB) and antibiotic cefixime trihydrate (CMT). The results highlight the significance of considering temperature (from 300.55 to 320.55 K) and electrolytes (NaBr, Na2SO4, Na3PO4, and CH3COONa (NaOAc)) effects when designing drug formulations. Conductometric method was utilised to compute and understand physicochemical parameters occurring during drug-surfactant micellization. The addition of sodium electrolytes favours the micellization of the TTAB and CMT system in aq. salts solution (a decrease of CMC was acquired) except at higher NaOAc concentrations. In all the solvents used herein, the CMC values were detected to be increased with the escalation of working temperature. The and expose the survival of hydrophobic interaction involving TTAB and CMT drug in aq. medium whereas both electrostatic and hydrophobic interaction are in function in aq. salts medium. As an extension of the thermodynamic assessment, the molar heat capacity were estimated and discussed. The thermodynamics of transfer (, , and ) and enthalpy-entropy compensation parameters for TTAB + CMT micelles were also analysed. This comprehension of drug-surfactant interaction holds utmost significance in the development of efficient drug formulations and the optimisation of drug delivery techniques.

Assessment and Biodegradation of Polycyclic Aromatic Hydrocarbons in Soil and Water Around Petroleum Products Depot Suleja, Nigeria.

Petroleum contamination constitutes a frequent incidence in various petroleum depots in Nigeria. In this study, the polycyclic aromatic hydrocarbons (PAHs) present in soil and water in communities around Petroleum Products Marketing Company (PPMC) Suleja, Nigeria, were evaluated and degraded using indigenous microorganisms. The samples sites were divided into 7 plots from where samples of water and soil were obtained: one within the PPMC depot, five from communities surrounding the depot, and the control 93,000km from the depot. The microbial counts were determined using spread plate inoculation technique on minimal salt media. The microbial isolates were characterized and identified based on their cultural, biochemical, and molecular characteristics. The potential of the microbial isolates to utilize 0.05 mL of diesel, kerosene, engine oil, and crude oil was determined in a Bushnell Haas Broth, and the biodegradation was determined by total viable cell counts and spectrophotometry. The ability of the isolates to mineralize PAHs was also evaluated in a minimum salt media. The bacterial isolates were species of Streptococcus, Pseudomonas, Staphylococcus, Proteus, Escherichia, and Bacillus, while species of Penicillium, Aspergillus, Mucor, and Rhizopus were isolated among the fungi. Aspergillus niger strain ATCC 1015 and Bacillus thuringiensis strain M43 showed high capacity to utilize the 16 priority PAHs. The pahE1 gene was used by Bacillus thuringiensis, Pseudomonas aeruginosa and A. niger, while Penicillium notatum used pahE2 gene for the degradation of the PAH. The current study identified microbial isolates that can utilize priority PAHs, making them beneficial for oil spill bioremediation in tropical environments.

The isolation of benzo[a]pyrene‐degrading strain and its cometabolic bioremediation with salicylic acid of long‐term PAH‐polluted soil

AbstractPolycyclic aromatic hydrocarbons (PAHs) are typical contaminants in soil, and the high‐molecular‐weight (HMW) PAHs are especially recalcitrant to remove. Microbial degradation as a promising approach has been used in PAH‐polluted soil remediation; however, the removal of HMW PAHs still needs to be further explored. In order to isolate more HMW‐PAH‐degrading strains and improve the removal of HMW PAHs in long‐term contaminated soil. Benzo[a]pyrene (BaP), as a representative HMW PAH was selected to explore the removal of HMW PAHs from soil. A BaP‐degrading strain named Achromobacter xylosoxidans B‐2 was isolated, and its degradation ability was explored in mineral salt medium (MSM) and PAH‐contaminated soil. Cosubstrates were added to enhance the removal of PAHs in soil. The results showed that A. xylosoxidans B‐2 could remove 87% of BaP at a concentration of 1 mg/L within 15 days in MSM. The average removal efficiency of HMW PAHs in soil was 19.92% after 30‐day bioremediation by A. xylosoxidans B‐2. Salicylic acid as cosubstrate increased the removal efficiency by 11.32%–14.66% for five‐ring PAHs and 9.72%–13.02% for six‐ring PAHs, respectively. The addition of cosubstrate not only improved the soil properties but also stimulated the soil microbial activity to enhance the removal of HMW PAHs. This study may provide new insights into bioremediation for HMW‐PAH‐contaminated soil.

Biohydrogen Gas/Acetone-Butanol-Ethanol Production from Agave Guishe Juice as a Low-Cost Growing Medium

Different strategies have been assessed for the revalorization of guishe to obtain biomolecules. The juice obtained after the mechanical extraction of guishe is rich in phytochemicals and sugars which can be converted to other products. The objective of the present study was to evaluate the production of hydrogen and butanol at different guishe juice concentrations (and therefore, different sugar concentrations) via fermentation in batch mode using Clostridium acetobutylicum ATCC 824. Fermentation assays were performed in triplicate under anaerobic conditions at 35 °C for 142 h. Guishe juice was supplemented with all components of synthetic medium (salts, vitamins and reducing agents), except glucose, and diluted at different concentrations: 20%, 40%, 60%, 80% and 100%. For comparison purposes, a control was carried out in a synthetic medium using glucose as carbon source. Results showed a maximum butanol concentration of 5.39 g/L using 80% guishe juice, corresponding to a productivity and yield of 0.04 g/L h−1 and 0.24 g/g, respectively. Meanwhile, the highest productivity (1.16 L H2/L d−1; 1.99 mmol H2/L h−1) and yield (18.4 L/kg) of hydrogen were obtained with 40% guishe juice. This study demonstrates the potential of guishe juice to be used as a low-cost substrate for hydrogen and butanol production.

General nitrogen regulation protein NtrC regulates the expression of nitrile hydratase and the synthesis of extracellular polysaccharide in Ensifer adhaerens CGMCC 6315

Ensifer adhaerens CGMCC 6315 contains two nitrile hydratases, CnhA and PnhA, which both convert the neonicotinoid insecticide acetamiprid to its amide metabolite. Here, we report that upregulation of PnhA and CnhA expression is related to nitrogen metabolism. Proteomic analysis showed that general nitrogen regulation protein NtrC was upregulated under nutrient deprivation. We thus constructed a ΔntrC mutant strain of E. adhaerens CGMCC 6315. In the ΔntrC strain, when cells were cultured in minimal salts medium supplemented with ammonium chloride, acetamiprid degradation and the expression of cnhA and pnhA were enhanced relative to those in wild-type E. adhaerens CGMCC 6315. In addition, NtrC negatively regulates synthesis of extracellular polysaccharides in this bacterium. The germination rate of soybean seeds was improved by inoculation with the ΔntrC strain of E. adhaerens CGMCC 6315 compared with the wild-type. This study is the first to report regulation of the expression of nitrile hydratase by NtrC, which is important for the practical remediation of pesticide pollution.

Biotransformation of Lignocellulosic Biomass Hydrolysate into Polyhydroxybutyrate Biopolymer via Ralstonia Eutropha

Currently, a rampant cultural shift is occurring in the modern world to progressively substitute fossil-derived plastics and shift to novel biomaterials that are benign to the environment owing to increased awareness of environmental sustainability along with the implementation of strict regulations worldwide. Polyhydroxyalkanoates (PHAs) are promising intracellular biodegradable polymers that have attracted considerable focus owing to their biocompatibility, biodegradability, non-toxicity and environment-friendly nature to function in diverse applications notably in the pharmaceutical, medical, textile, materials, fuel, agricultural industries. Nonetheless, despite its huge market potential, the commercial growth of PHA is achieved on a small extent only, since the cost-effectiveness of this product is highly debatable owing to the high production cost of processing the carbon substrate. The goal behind this research study is to explore the possibility of exploiting low-cost carbon substrates from low-value lignocellulosic materials that would have otherwise been discarded as waste and add stress to the landfill to manufacture biopolymer compounds that are used in everyday lives as well as to enhance the functionality and yields of glucose from PHA substrates that can undergo industrial upscaling. One of the major challenges of transforming lignocellulosic biomass into fermentable sugars is the recalcitrant nature of the fibre which renders it very resistant to the release of sugars for fermentation. Since lignocellulosic biomass has a specific attribute such as an extremely coordinated matrix which renders it very resistant to the release of sugars for fermentation owing to biological degradation, a pre-treatment phase is necessary prior to the hydrolysis stage for the transformation of the fermentable sugars. This study focuses on the biosynthesis of biopolymers from lignocellulosic biomass through sustainable approaches such as enzyme and microbial activities in order to examine its viability as a replacement for traditional polymers. Cupriavidus Necator H16 (Ralstonia Eutropha) having 8×108 CFU/ml viable colonies were cultured at 30 oC and was inoculated in submerged fermentation of M9 minimal salt medium using 1% reducing sugar from Furcraea Foetida as carbon source. Batch fermentation of PHB in submerged cultivation conducted for a residence time from 0 to 48h resulted in a dry cell weight from 0.32±0.05% to 1.62±0.05%. The nitrogen limiting phase was achieved after 48h and 17.05±0.35% of PHB was extracted from 3ml of the fermentation broth. The PHB yield was dramatically lower than reported optimal yields of 37.55 to 97.80% from works of literature. Nonetheless, Fourier-transform infrared spectroscopy (FTIR) spectroscopy revealed characteristics bands for carbonyl, methine and ester groups along with intermolecular hydrogen bonds in the biopolymer. Sudan Black B and FTIR spectrum demonstrate that PHB biosynthesis successfully bioaccumulates inside the cells of Ralstonia Eutropha using cellulose from Lignocellulosic biomass (LCB) as carbon source. Hence, the process needs to be optimized in terms of variables such as inoculum size, inoculum concentration, incubation time and salt medium conditions in order to maximise the production of PHB from Furcraea Foetida in Ralstonia Eutropha cultivation.

KAJIAN KETAHANAN BETON DENGAN TAMBAHAN CAMPURAN FLY ASH DAN LIMBAH KARBIT DALAM MEDIA ASAM DAN GARAM (DURABILITY STUDY OF SELF COMPACTING CONCRETE WITH ADDED A MIXTURE OF FLY ASH AND CALCIUM CARBIDE WASTE IN ACID AND SALT MEDIUM)

Cement is one of the building blocks of concrete. However, it releases about one ton of carbon dioxide (CO2) gas for every ton of cement produced. Therefore, it is necessary to replace cement in the manufacture of concrete. It is known that a mixture of fly ash and calcium carbide waste has a chemical composition that resembles cement containing silica, alumina, and calcium oxide compounds so that it has the potential to replace cement in making self-compacting concrete. This research was conducted by utilising fly ash waste and carbide waste as additional materials to replace the use of cement by 35% in self compacting concrete. The composition of the waste used in the concrete mix in this study consisted of 25% fly ash waste and 10% calcium carbide waste. Analysis of the elemental composition of self-compacting concrete containing fly ash and calcium carbide waste was obtained from XRF data, the compressive strength of self-compacting concrete samples was tested, their resistance in acid and salt media was studied through the results of compressive strength test analysis, then compared with self-compacting concrete containing 100% cement. The XRF results showed that the elemental composition of the mixture of fly ash, calcium carbide waste, and cement was similar to that of cement alone, but the CaO and SiO2 content of the mixture was still higher than that of cement alone. Based on the compressive strength test analysis results, it was found that the compressive strength values of the self-compacting concrete samples were lower than the compressive strength values of the control of self-compacting concrete samples (cement only). Self-compacting concrete samples soaked in acid and salt media for 28 days showed a decrease in compressive strength, both in self compacting concrete containing a mixture of fly ash, calcium carbide waste, and cement, and concrete containing only cement. The compressive strength values of the fly ash and calcium carbide waste on self-compacting concrete samples in this study were at the range of 28 MPa to 29 MPa, still within the SNI 2847-2019 quality standard, which is the normal concrete quality standard with a compressive force of 15-30 MPa, even though they have been exposed to acid or salt. This allows efforts in replacing cement in self compacting concrete by adding the composition of fly ash waste and calcium carbide waste.

Leaching of Copper Concentrates with Iodized Salts in a Saline Acid Medium: Part 2-Effect on Chloride Concentration and an Aerated System.

To enhance the leaching of chalcopyrite concentrates, this study evaluated a new process for extracting copper using iodized solutions and sulfuric acid diluted in seawater without pressure or high temperatures. The work involved a leaching test carried out under various conditions by varying the concentrations of chloride ions, H2SO4, and an evenly distributed oxygen supply in an aeration system. It was demonstrated that Cl- ion addition could promote the chalcopyrite-leaching process. The leaching efficiency of copper reached 70% after 96 h. However, a chloride ion dosage excess can have the opposite effect on extraction, reducing copper recovery. XRD and SEM-EDS results showed that cuprous chloride (CuCl) was formed at high dosages (>0.5 M); meanwhile, at a lower dosage, elemental sulfur (S) was formed in the presence of sulfuric acid solution and seawater medium. In contrast, in an aerated system, surface roughness markedly increased due to continuous oxidation on the surface of the ore. This change in morphology and the high value of the redox potential, given by the aerated system and the acidic environment, allowed copper recovery of up to 70% after 96 h. The results showed that an aerated system is the most effective factor in chalcopyrite concentrate leaching.

Enzymatic degradation and metabolic pathway of phenanthrene by manglicolous filamentous fungus Trichoderma sp. CNSC-2

Manglicolous filamentous fungi release extracellular lignolytic enzymes that can readily degrade polycyclic aromatic hydrocarbons (PAHs). The present study emphasizes the role of the extracellular enzyme in phenanthrene degradation by the manglicolous fungus Trichoderma sp. CNSC-2 isolated from the Indian Sundarban mangrove ecosystem. The removal efficiency reached 64.05 ± 0.75 % in 50 mg l−1 phenanthrene-amended mineral salt medium at pH 5.6 after 10 days of incubation. Phenanthrene removal was optimized at different pH, nutrient sources, and Cu2+ concentrations. The degradation significantly increased to 67.75 ± 4.32 % at pH 6 (P < 0.0001). The addition of Cu2+ (30 mg l−1) increased the degradation to 78.15 ± 0.36 % (P < 0.0001). The validation experiment confirmed the increase in phenanthrene degradation up to 79.9 ± 1.67 % under optimized conditions. The Lac1 and CytP450 genes encoding for extracellular and intracellular enzymes, respectively, were identified. The GC-MS derived phenanthrene degradation metabolites, i.e., phthalic acid, isobutyl 2-pentyl ester derivative, 1, 2 benzene dicarboxylic acid, butyl 2-methyl propyl ester derivative, TMS derivative of benzoic acid and 3,5 dihydroxy benzoic acid determined two possible metabolic pathways. The laccase enzyme activity was higher in the presence of Phe+Cu2+ (P < 0.0001), indicating the enzyme induction potential of PAH and Cu2+ ions. Purified laccase had a molecular weight of 45 kDa and was highly stable at pH 4–6 and temperature 20–50 °C. The enzyme retained 47 %, 87 %, and 63 % of enzyme activity at 30 mg l−1 concentration of Pb2+, Cd2+, and Hg2+. However, laccase activity was induced by 1.37 folds in the presence of 30 mg l−1 Cu2+ concentration. Thus, the study suggests the potential role of Trichoderma sp. CNSC-2 in phenanthrene degradation.