Functional Group Profiles Research Articles

Atomic-level insights into CeO2 performance: Chemical interactions in CMP explored through CeO2-SiO2 studies

This study explores the effects of atomic-level factors on the performance of CeO2 when interacting with SiO2 films. It specifically examines how different precursors, the ratio of Ce to OH, and reaction temperatures influence outcomes. Our findings reveal that smaller particles, around 5 nm in size, created using a Ce4+ precursor, are more effective at removing SiO2 films compared to larger, more crystalline particles from a Ce3+ precursor. This is due to their increased interaction with the SiO2 film during the polishing process, challenging the conventional emphasis on mechanical abrasion in chemical mechanical planarization (CMP) and highlighting the crucial role of chemical interactions. Further analysis through FT-IR and TGA-FTIR techniques showed distinct functional group profiles on the ceria surfaces. Ceria derived from Ce4+ exhibited a higher presence of OH and NO3 groups, enhancing adsorption capabilities, as verified by CHN analysis. Importantly, first-principles calculations identified these surface groups as key to improving adhesion to SiO2 films. Surfaces of amorphous CeO2, rich in -OH and -NO3 groups, showed significantly higher adhesion levels than their crystalline counterparts, connecting crystallinity to chemical functionality. This new insight leads to the possibility of designing next-generation CeO2 abrasives with increased chemical activity.

Nano Modifications of Biochar to Enhance Heavy Metal Adsorption from Wastewaters: A Review.

Biochar (BC) is a carbon-rich material that can be obtained by thermal decomposition of agricultural solid waste under oxygen-limited conditions. It has received increasing attention as a cost-effective sorbent to treat metal-contaminated water due to attributes such as high porosity and the presence of various functional groups. The heavy metal (HM) sorption and removal capacity of BC can be enhanced by developing novel biochar nanohybrids (BNHs) that can be produced via surface modification of BC with nanomaterials. Loading of nanomaterials on the biochar surface can improve its physicochemical properties through alterations in the functional group profile, porosity, and availability of active sites on the BC surface which can enhance the HM adsorption ability. This manuscript provides information on preparation of nano-based biochar hybrids emanating from the type of modifying agent for the removal of different HM ions from wastewaters, and the underlying mechanisms have been discussed. Further, this compilation discusses published literature depicting the influence of different processes of preparation on the physicochemical properties and adsorption capacity of nanobiochar hybrids. The potential risks of BNHs have been reviewed to effectively avoid the possible harmful impacts on the environment, and future research directions have been proposed.

Herb Polysaccharide-Based Drug Delivery System: Fabrication, Properties, and Applications for Immunotherapy.

Herb polysaccharides (HPS) have been studied extensively for their healthcare applications. Though the toxicity was not fully clarified, HPS were widely accepted for their biodegradability and biocompatibility. In addition, as carbohydrate polymers with a unique chemical composition, molecular weight, and functional group profile, HPS can be conjugated, cross-linked, and functionally modified. Thus, they are great candidates for the fabrication of drug delivery systems (DDS). HPS-based DDS (HPS-DDS) can bypass phagocytosis by the reticuloendothelial system, prevent the degradation of biomolecules, and increase the bioavailability of small molecules, thus exerting therapeutic effects. In this review, we focus on the application of HPS as components of immunoregulatory DDS. We summarize the principles governing the fabrication of HPS-DDS, including nanoparticles, micelles, liposomes, microemulsions, hydrogels, and microneedles. In addition, we discuss the role of HPS in DDS for immunotherapy. This comprehensive review provides valuable insights that could guide the design of effective HPS-DDS.

Understanding biochemical defense and phytoremediation potential of Leucas aspera in crude oil polluted soil.

The phytoremediation potential and enzymatic defense of a medicinal herb Leucas aspera was studied in the crude oil contaminated soil. The productivity, antioxidants, and phytochemical and functional group profiles of the plant species in stress conditions were investigated. Besides, changes in enzymes, beneficial bacterial population, and physico-chemical and total oil and grease (TOG) profiles in the contaminated soil were also studied. The results showed improvement in physico-chemical conditions, increase in beneficial bacterial population (4.1-5.4 folds), and decrease in TOG (31.3%) level of the contaminated soil by end of the experimental trials. The L. aspera treated contaminated soil showed enhancement in dehydrogenase (32.3%), urease (102.8%), alkaline phosphatase (174.4%), catalase (68.5%), amylase (76.16%), and cellulase (23.6%) activities by end of the experimental trials. Furthermore, there were significant variations in leaf area index, chlorophyll, and biomass contents of the experimental plant as against the initial level and control. Besides, the significant reduction in IC50 values (24-27.4%) of L. aspera samples grown in contaminated soil confirms the strong antioxidant enzymatic defense of the plant species against the crude oil associated abiotic stress. The Fourier-transform infrared (FT-IR) analysis confirmed the uptake and metabolism of aliphatic hydrocarbons, aldehydes, alkyl halides, and nitro compounds by the experimental plant from the contaminated soil.

A novel biowaste-based biosorbent material for effective purification of methylene blue from water environment

The biowaste left over from the fixed oil biorefinery process of Nigella sativa L. plant was used as a new biosorbent for the biosorption of synthetic dye of methylene blue from water environment in this study. The main variables of biosorption operation such as methylene blue concentration, time, pH, and biosorbent amount were optimized by the batch-type experiments. The characterization, kinetics, equilibrium, and thermodynamics works were conducted to show the nature of methylene blue biosorption. The studies of Fourier transform infrared spectroscopy and Scanning electron microscopy indicated that the biosorbent possessed an inhomogeneous surface morphology including many cavities and protuberances, and a rich functional group profile. The optimum values of operating variables studied for the biosorption of methylene blue were determined as methylene blue concentration of 15 mg L−1, time of 360 min, pH of 8, and biosorbent amount of 10 mg. The experimental data of methylene blue biosorption followed the kinetics and isotherm models of pseudo-second-order (R 2: 0.98, AdjR 2: 0.98, and RMSE: 8.97) and Dubinin-Radushkevich (R 2: 0.99, AdjR 2: 0.98, and RMSE: 6.84), respectively, based on the statistical tests of coefficient of determination (R 2), adjusted coefficient of determination (AdjR 2), and root mean squared error (RMSE). The biosorption of methylene blue was a physical, spontaneous, and energetically favorable process (E DR: 3.48 kJ mol−1 and ΔG°: (−14.51) − (−10.02) kJ mol−1). This residual biological material from the fixed oil biorefinery process exhibited higher biosorption performance (187.46 mg g−1) than own unrefined (virgin) form and its modified, activated, and composite forms and many other sorbents reported in the literature. Hereby, the current work showed that this novel biowaste-based material could be used as an environmentally and economically promising biosorbent to effectively purify methylene blue from aquatic environment.

Pengaruh Konsentrasi Asam Stearat dan Lama Pengadukan Proses Gelatinisasi terhadap Karakteristik Komposit Bioplastik Maizena-Glukomanan

This study aims to determine the effect of stearic acid concentration and the stirring time and also the interaction of both on the characteristic of the cornstarch-glucomannan bioplastic composite and also to determine the cornstarch-glucomannan bioplastic composite on the concentration of stearic acid and stirring time produce the best characteristic. The research used a factorial randomized block design. The first factor is the concentration of stearic acid consisting of 4 levels that is 0.1%; 0.2%; 0.3%; 0.4% (w/w). The second factor is stirring time consisting of 4 levels that are 3, 4, 5, 6 minutes. The observed variable on this study were tensile strength, elongation at break, modulus young, swelling, water vapour transmission rate (WVTR), biodegradation, and functional group profile. The data were analyzed of variant and continued with Duncan Multiple Range Test (DMRT). The result of this study indicate that the concentration of stearic acid and stirring time of gelatinization process has a very significant effect on the tensile strength, modulus young, swelling, water vapour transmission rate (WVTR), biodegradation, but the concentration of stearic acid had no significant effect on elongation at break. The interaction between treatments has a very significant effect on elongation at break. Concentration stearic acid 0.4% and stirring time 6 minutes treatment resulted in the best bioplastic composite with a tensile strength 22.17 MPa, elongation at break 8.55%, modulus young 260.87 MPa, swelling 81.58%, water vapour transmission rate 0.638 g/m2.hour and biodegradability 7 days. The composite of cornstarch-glucomannan and stearic acid consists of hydroxyl (O-H), carboxyl (C-O), carbonyl (C=O), and hydrocarbon (CH2)n.
 Keywords : bioplastic, cornstarch, glucomannan, stearic acid, stirring time

Analysis of natural wax from Nelumbo nucifera leaves by using polar and non-polar organic solvents

Nelumbo nucifera (lotus) is a unique aquatic plant. Its leaves are covered with superhydrophobic wax layer which protects it from the environmental wearing. In this study, the extraction yield and the functional group profile of crude lotus leaf natural wax have been observed. The lotus leaf wax has been extracted by using many polar and non-polar solvents through different extraction methods. The superhydrophobic wax was successfully extracted from the non-polar solvents i.e. benzene, toluene, xylene, petroleum ether; whereas the polar solvents used (ethanol and ethyl acetate) did not extract the superhydrohobic wax. The results show the highest extraction yield was observed with xylene and the extract in toluene exhibited the best lotus leaf surface-like behavior. Conventional extraction method of maceration provides a slightly higher extraction yield compared to the Soxhlet extraction. For the extract in xylene, maceration provided an extraction yield of 4.37 % and Soxhlet extraction provided a yield of 3.54 %. The TLC performed on the extracts depicted the presence of both polar and non-polar compounds. The FTIR analysis confirmed the presence of alkane chains in the crude natural wax extract. If utilized properly, the lotus leaf natural wax can help mankind in providing cost-effective and affordable waterproofing solutions.

Phytochemical Screening, Spectrum Profile of Functional Groups, and Effervescent Formulation of Kepok Banana Peels Stem Extract

Kepok banana plants contain secondary metabolites such as tannins and flavonoids. Tannins and flavonoids have various properties for human health. Research has been carried out to identify secondary metabolite compounds (tannins, flavonoids, and saponins) by using the phytochemical screening method to see the functional group profile contained in the extract of kepok banana stem waste. Kepok banana stem waste was extracted in 96% ethanol, then evaporated and screened phytochemically. This extract was used to prepare effervescently. Screening results showed that tannin and flavonoids were identified by the appearance of the following color black-green and dark red, respectively. Meanwhile, saponins were negative because the foam formed had a height of 0.3 cm and did not meet the saponins' positive requirements (1-3 cm high foam and stable for 5 minutes). Identification of functional groups in the extract of kepok banana stem waste using Fourier-transform Infrared Spectroscopy (FTIR) showed that C-C stretching in the area 2927.24 cm-1, O-H stretching in the 3423.87 cm-1 area, C=O stretching in the 1648.87 cm-1 area. Also appeared bending CH2 in the region of 1421.45 cm-1, and C-C in the area of 1149.98 cm-1. The characteristics of three different formulas (A, B, and C) of effervescent have been investigated: the moisture content of 2.51%; 2.55%, and 2.52%, respectively. Then, flow rate of 8.81 g/s; 8.83 g/s; and 8.82 g/s, compressibility of 14.5%; 14.4%; and 14.5%, and a pH of 5.97; 5.98; and 5.97 respectively. All parameters are eligible.

Morphological, thermal, and pasting properties of cocoyam (Xanthosoma sagittofolium) starch from three locations in Mollucas Islands

This study investigated the morphological, thermal, and pasting properties of cocoyam starch from three locations in Mollucas islands. The islands are Buru, Porto, and Saumlaki. The results showed that starch granules were round and polygonal in shape, and the size varied significantly in range of 11,42 – 12,99 μm, while the range of crystallinity of the three cocoyam starches studied was 11,81% -16,61% and crystal type was A, this was a type for tubers. The thermal properties of cocoyam starch measured by DCS showed the results of onset (To), peak (Tp), endset (Te) and enthalpy (ΔH) in the range of To: 76-77oC, Tp: 78-80oC, Te: 82-86oC and Δ H (J / g): -130.0 - (-) 175.76 respectively. The FTIR analysis showed the functional group profiles of native starches studied had the highest absorption spectra of 3286.70-3325.86 cm-1 (O-H group vibrations). The peak, trough, breakdown, setback, and final viscosities were in the range of each PV: 4601 - 5155 RVU, TV: 2623 - 2874 RVU, BV: 1978 - 2287 RVU, FV: 4026 - 4176 RVU, SV: 1240 - 1403 RVU, Pt (Min) 7.87 - 8.40, PT (o C): 79.90 - 81.70.

Efficiency of Catalytic Liquid Hot Water Pretreatment for Conversion of Corn Stover to Bioethanol.

Lignocellulose is a promising raw material for the production of second-generation biofuels. In this study, the effects of acid-catalyzed liquid hot water (LHW) on pretreatment of corn stover (CS) for subsequent hydrolysis and conversion to ethanol were studied. The effects of reaction temperature, acid concentration, and residence time on glucose yield were evaluated using a response surface methodology. The optimal condition was 162.4 °C for 29.5 min with 0.45% v/v of sulfuric acid, leading to the maximum glucose yield of 91.05% from enzymatic hydrolysis of the cellulose-enriched fraction. Conversion of the solid fraction to ethanol by simultaneous saccharification and fermentation resulted in a theoretical ethanol yield of 93.91% based on digestible glucose. Scanning electron microscopy revealed disruption on the microstructure of the pretreated CS. Increases of crystallinity index and surface area of the pretreated biomass were observed along with alteration in the functional group profiles, as demonstrated by Fourier transform infrared spectroscopy. This work provides an insight into the effects of LHW on the enzymatic susceptibility and modification of the physicochemical properties of CS for further application on bioethanol production in biorefinery.

Habitat-specific environmental factors regulate spatial variability of soil bacterial communities in biocrusts across northern China's drylands

Biocrusts are common biotic components in dryland ecosystems worldwide, they contain diverse soil organisms and effectively enhance soil stability and perform a series of key ecological functions. However, the geographical pattern of microbial communities in biocrusts is rarely assessed, despite it is closely related to the spatial variation of ecosystem functions in drylands. We assessed soil bacterial communities in biocrusts across four ecosystems (Gobi, desert, desert steppe and grassland) in a precipitation gradient (16–566 mm yr−1) in northern China. Bacterial OTU number and phylogenetic diversity did not linearly increase with decreasing aridity, they were significantly lower in Gobi and similar among desert, desert steppe and grassland. Soil bacterial community composition in Gobi and desert were different than those in desert steppe and grassland, and they were similar between Gobi and desert, this suggests the key role of habitat in structuring soil bacterial communities. The geographic pattern of soil bacterial communities was strongly influenced by both geographic distance and environmental factors. The first explanatory factor for the geographic variation of bacterial community dissimilarity differed among four ecosystems, being aridity in Gobi and desert, precipitation in desert steppe, and soil inorganic nitrogen in grassland. The geographic pattern of the bacterial functional group profile showed a similar pattern with community composition across four ecosystems, and the groups of containing mobile elements and gram negative bacteria were more abundant in drier habitats of Gobi and desert. Our results reveal the non-linear changes in diversity, composition and functional group of soil bacterial communities in biocrusts across the precipitation gradient from hyper-arid to semi-humid regions, and suggest that the geographic distance and habitat-specific environmental factors determine the distribution of soil bacterial communities in different ecosystems.

Effect of ultrasound‐ethanol pretreatment on drying kinetics, quality parameters, functional group, and amino acid profile of apple slices using pulsed vacuum drying

AbstractThe influence of ultrasound‐ethanol (US‐E) pretreatment durations (10, 20, and 30 min) on apple slices dried with varied temperatures (60, 70, and 80°C) using pulsed vacuum dryer was investigated. The results showed that untreated sample (control) took 375, 325, and 225 min to achieve a constant weight of drying whereas drying time for 30 US‐E samples were 275, 225, and 175 min, indicating that 30 US‐E reduced the total drying time by 26.66, 30.77, and 22.22% at 60, 70, and 80°C, respectively. Moisture effective diffusivity and activation energy were in the range of 1.98–4.08 × 10−8 m2/s and 12.58–23.43 kJ/mol, respectively. Color (L*, a*, b*) and texture were affected significantly (p < .05) at high temperature and longer US‐E. Shorter US‐E duration and lower temperature could preserve most functional groups. Also, total free amino acid values were significantly higher at lower temperature and longer US‐E pretreatment.Practical applicationsDrying time, nutrient retention, and energy efficiency are at the heart of the food industry. The remarkable reduction obtained in the drying time as well as retaining of some functional groups (nutrients composition) with the use of ultrasound‐ethanol as a pretreatment for pulsed vacuum dryer indicates that this technique will serve a great purpose in food processing industries. This in effect will reduce production cost thereby making the business operations of food processors competitive as it provides value proposition to their customers.

Synthesis of poly hydroxypropyl methacrylate cryogel incorporated with Zn/Ce substituted hydroxyapatite nanoparticles for rejuvenation of femoral fracture treatment in a rat model

Designing biomimetic biomaterials influenced by the common complex structure of hard tissues is yet a test these days. The control of bio-mineralization procedure onto biomaterials should be assessed before the use in medical applications. Coming to the bone rejuvenation applications, this work assessed the in vitro antibacterial activity and interacting between osteoblast cells (MG63) on poly (hydroxypropyl methacrylate) (PHPMA) cryogel consolidated with Zn/Ce substituted hydroxyapatite (MHAp) nanocomposite (PHPMA/MHAp). Osteoblast cell multiplication, morphology, and metabolic action were assessed through various conventions. The functional group, texture, mechanical properties, and protein adsorption profiles of the fabricated nanocomposite were analyzed by the FTIR, XRD, SEM, and mechanical examinations, respectively. The bacterial activity of nanocomposites was additionally assessed against E. coli and S. aureus microorganisms, individually. Nanocomposite advanced endo-chondral ossification at the messed up parts of the bone deformity than cryogel did. These results recommend that PHPMA/MHAp nanocomposites joined the good innate properties of each polymer and bioceramic, giving a mechanically powerful, cell-responsive, and permeable stage for hard tissue applications.

KARAKTERISTIK KOMPOSIT BIOPLASTIK GLUKOMANAN DAN MAIZENA DALAM PENGARUH VARIASI SUHU DAN WAKTU GELATINISASI

The aim of this study was to determine the effect of the temperature and time of gelatinization and its interactions on the composite characteristics of bioplastics glucomannan and cornstarch with to obtain gelatinization temperature and time to produce the best bioplastic glucomannan and cornstarch composites. This study used factorial randomized block design. Factor 1 gelatinization temperature consisting of 3 levels, namely 70 ± 1; 75 ± 1; 80 ± 1°C. Factor 2 is gelatinization time, for 2, 3 and 4 minutes. Variables observed included tensile strength, elongation at break, young modulus, swelling, biodegradation and functional group profile. The data were analyzed for diversity and continued with the BNJ test. The results showed that the temperature and time of gelatinization and their interactions had a very significant effect on tensile strength and elasticity. The temperature and time of gelatinization had a very significant effect but did not interact with elongation and did not significantly affect the swelling and biodegradation of bioplastic composites. The best bioplastic glucomannan and maizene composites were at a temperature treatment of 80 ± 1°C and 4 minutes gelatinization time with tensile strength characteristics (3.390 mpa); elasticity (35.811 mpa); elongation at break (12.3%); swelling (68.13%); degradation time of 8 days and contains hydroxyl (O–H) functional groups, alkene (C– H), carboxyl (C–O), carbonyl (C=O) and alkyne (C?C).
 Keywords : Composites bioplastic, glucomannan, maizena, temperature and time of gelatinization

Quantitative analysis of native reactive functional groups on carbon fiber surface: An electrochemical approach

Quantitative insight into the distribution of different reactive functional groups on carbon fiber surfaces is essential for designing surface modification strategies and tailoring matrix-fiber interactions. In order to determine the amount of –OH, –COOH and –NH2 functionalities on carbon fiber surface, we covalently bound ferrocene structures to these moieties via a set of reactions including acylation, ester coupling and Schiff base formation. Following cyclic voltammetry experiments using the functionalized fibers as working electrodes, the amount of ferrocene structures could be conveniently calculated and the reactive functionalities quantitatively determined in knowledge of their distinct reactivity profile. The electrochemical experiments and proceeding of the corresponding reactions were further substantiated by analyzing the high-resolution C1s, O1s and Fe2p X-ray photoelectron spectra. It appears that the amount of reactive functional groups are quite high (~1.8 × 1014 molecules cm−2), and these functionalities consist mainly of –OH groups (~97%). The amount of surficial –NH2 (~2.7%) and –COOH (~0.3%) groups is rather low. Our study might open up new avenues towards novel functionalization strategies targeting –OH groups, and the electrochemical method can provide new insights into the functional group profile when carbon fiber surface is oxidized, as we show on a case study.

Extraction and characterization of gelatin from skin trimming pickled waste of tannery

Hides and skins, the raw material used in the leather industry are a by-product of the meat industry. The tanning process results in a lot of waste, including solid and liquid waste. Pickled skin trimming is one of the solid waste derived from the tanning process and has a high protein and acid content. Suspected acid on the pickled skin trimming can be used to produce type A gelatine without the addition of acid from the outside. Pickled skin trimming was washed using limited water intended to remove the salt and to maintain the acid content so that the collagen can be partially hydrolyzed in-situ into gelatin. The purpose of this research was to determine the characteristics of pickled skin trimming’s gelatin was produced from in-situ acid hydrolysis. The variations of washing were 1:10; 1:15; 1:20; 1:25; 1:30 pickled skin parts: parts of water (w/v). Hydrolysis for 48 hours by adding water as much as 5 parts by weight of the skin. Extraction with water as much as 4 parts by weight of the skin at a temperature of 70-80° C for 3 hours. The highest yield of 49.73% was obtained from the salt separation with pickled skin/water ratio of 1:20(w/v). Proximate composition, pH, functional group profiles, molecular weight distribution, and viscosity of gelatin extracted from pickled skin trimming produced similar characteristics (P>0.05). Gelatin had the characteristic that met GMIA standard for moisture content and viscosity, also had identical functional properties with commercial gelatin. Therefore, gelatin from pickled skin trimming waste can be utilized for pharmaceutical, biomaterial, tissue engineering and cosmetic industries with relatively cheap price.

Effects of Wood Density on Aquatic Insect Communities in a Cuban Montane Rainforest Stream.

We tested whether hardness or different wood carbon densities, considered as the concentration of carbon structural compounds, influence functional feeding groups and species richness of aquatic insects in a tropical stream. We expected that harder woods would harbor aquatic insect communities with species richness and functional food group profile different from softwoods. We also expected that collector-gatherers and collector-filterers will be more abundant in softwood because harder woods are less substrate suitable for biofilm production. Aquatic insects associated with the following plants were analyzed: Gomidesia lindeniana with high-density, Psychotria grandis with medium-density, and Meriania leucantha with low-density wood. Diptera and Ephemeroptera were the most abundant groups sampled in the woods. Psychotria grandis shows higher concentrations of lignin, cellulose, and hemicellulose, followed by G. lindeniana and M. leucantha. Breakdown rates are different among plant species with M. leucantha having four times highest breakdown rates and on average three more species in the species richness value. We did not find significant differences in the composition of insect species associated with the plants. We found evidence that the richness and functional organization of aquatic insect communities were mostly related to the breakdown rates and lignin amount of the woods. Plants that decompose faster on average have three more species and two more insect functional groups. Our findings suggest that the loss of high carbon density trees in tropical forests can affect aquatic biodiversity.

Of mammals and bacteria in a rainforest: Temporal dynamics of soil bacteria in response to simulated N pulse from mammalian urine

Abstract Pulse‐type perturbation through excreta by animals creates a mosaic of short‐term high nutrient‐load patches in the soil. How this affects microbial community composition and how long these impacts last are important for microbial community dynamics and nutrient cycling. Our study focused on the short‐term responses to N by bacterial communities and ‘functional groups’ associated with the N cycle in a lowland evergreen tropical rainforest. We applied a single urea pulse, equivalent to urine‐N deposition by medium‐sized mammals to simulate N enrichment and changes in soil N availability, and analysed soil bacterial communities using molecular methods, before and after urea application. Urea addition increased mineral N availability and changed bacterial community composition, from phylum to operational taxonomic unit levels, however, taxon richness and diversity were unaffected. Taxa involved in the physiologically “narrow” processes of nitrification (e.g. Nitrosospira) and denitrification (e.g. Phyllobacteriaceae, Xanthomonadaceae and Comamonadaceae) increased their relative abundance, while N2‐fixers (e.g. Rhodospirillales, and Rhizobiales) decreased after treatment. While a temporal legacy on both community composition and functional group profile was observable 58 and 159 days after treatment, at the latter date bacterial communities were already tending towards pre‐treatment composition. We suggest that pulse‐type perturbation by mammal urine that occurs on a daily basis has strong short‐term effects on patch dynamics of soil microbiota and N availability. Such a spatio‐temporally dynamic soil environment enhances overall microbial richness and diversity, and contributes to the apparent temporal resilience of community composition. A plain language summary is available for this article.

Chemical and physical characteristics of carrageenan extracted from Eucheuma spinosum harvested from three different Indonesian coastal sea regions

SUMMARYCarrageenan extracted from Eucheuma spinosum harvested from three different coastal sea regions, where this alga has been mainly cultivated, were determined for their chemical and physical characteristics. The carrageenan was extracted from the seaweed using hot alkali followed by precipitation, drying, and milling. The carrageenan properties were determined in terms of yield, ash, mineral, sulfate content, functional group, molecular weight, and viscosity profile. Physical characteristics of carrageenan were evaluated by a texture analyzer for gel strength and a rapid visco analyzer for viscosity. The yield of carrageenan from Sumenep (34.81 ± 5.83%) and Takalar (37.16 ± 3.26%) was found to be relatively higher than that of Nusa Penida (25.81 ± 1.93%). The calcium content was higher than magnesium, potassium and sodium content, and no cadmium, lead, mercury, and arsenic detected in all carrageenan. The ash content was around 29%; while, the sulfate content was in the range of 30–32%, and those were not different in all carrageenan. The presence of sulfate content was identified by FTIR at absorption band of 1373 cm−1. It was found that the molecular weight of carrageenan from Takalar were relatively higher and the gel strength of carrageenan from Takalar were significantly higher than that of carrageenan from Nusa Penida and Sumenep. Likewise, upon cooling from 80 to 20°C, the viscosity profile of carrageenan from Takalar characterized by higher viscosity compared to that of carrageenan from Sumenep and Nusa Penida. These results indicated that carrageenan from Nusa Penida, Sumenep, and Takalar were identified as iota‐carrageenan with similar physico‐chemical characteristics except for the gel strength, viscosity profile upon cooling from 80 to 20°C and the yield.

Metal Biosorption in Single‐ and Multi‐Metal Solutions by Biosorbents: Indicators of Efficacy in Natural Wastewater

Metal biosorption by a mixed‐microbial biosorbent of Stenotrophomonas maltophilia (bacterium) and Saccharicola bicolor (fungus) was compared against their respective single biosorbents to determine their efficacies in removing Pb, Cu, Zn, and Cd in single‐ and multi‐metal solutions. The multi‐metal solutions mimic natural wastewater which may interact differently between metal ions‐biosorbent, as well as between the metal ions. The results revealed that application of S. maltophilia (single, Sm) was the most effective, followed by mixed‐biosorbent (MB), then S. bicolor (single, Sb); occurring in both single‐ and multi‐metal solutions. The biosorbents preferred Cu > Pb > Cd > Zn in both metal‐solutions, with Sm demonstrating superior biosorption for all metals compared to other biosorbents. Attenuated total reflectance‐Fourier transform infrared spectroscopy (ATR‐FTIR) analysis detected different functional group profiles present on mixed biosorbent compared to the respective single forms, which may have influenced metal biosorption. All biosorbents adsorbed most of the metals via a rate‐limiting step indicated by compliance to pseudo‐second order kinetic. The biosorbent Sm was identified to having the most potential for further development as useful biosorbent for application in natural wastewater.