Displaying all 11 publications

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  1. Krishnan, Santhana, Mimi Sakinah Abdul Munaim, Zularisam Abdul Wahid, Chua, Yeo Gek Kee, Chew, Few Nee
    MyJurnal
    Monoclonal antibodies (mAbs) are unique and specific drug molecules targeting the treatment of various diseases such as arthritis, immune disorders, infectious diseases, and cancer etc. Different methods such as antibody coupled affinity chromatography, hydrophobic interaction chromatography, etc., can be applied to purify mAbs from various sources. This article provides a simple, cost effective, preparative native-polyacrylamide gel electrophoresis (n-PAGE)technique to purify mAbs expressed in H-192 cells (Hybridoma murine cell lines) against an antigen i.e. 17-alpha-hydroxyprogesterone (17-OHP), which further can have diagnostic application to detect Congenital Adrenal Hyperplasia (CAH). Furthermore, different parameters such as concentration and volume of the feedstock (medium containing antibodies), pore size of gel, height of resolving gel etc. were optimized to obtain the maximum purity and yield of mAbs.
  2. Jadhav P, Khalid ZB, Zularisam AW, Krishnan S, Nasrullah M
    Environ Res, 2021 Sep 17;204(Pt B):112043.
    PMID: 34543635 DOI: 10.1016/j.envres.2021.112043
    Several strategies have been proposed to improve the performance of the anaerobic digestion (AD) process. Among them, the use of various nanoparticles (NPs) (e.g. Fe, Ag, Cu, Mn, and metal oxides) is considered one of the most effective approaches to enhance the methanogenesis stage and biogas yield. Iron-based NPs (zero-valent iron with paramagnetic properties (Fe0) and iron oxides with ferromagnetic properties (Fe3O4/Fe2O3) enhance microbial activity and minimise the inhibition effect in methanogenesis. However, comprehensive and up-to-date knowledge on the function and impact of Fe-NPs on methanogens and methanogenesis stages in AD is frequently required. This review focuses on the applicative role of iron-based NPs (Fe-NPs) in the AD methanogenesis step to provide a comprehensive understanding application of Fe-NPs. In addition, insight into the interactions between methanogens and Fe-NPs (e.g. role of methanogens, microbe interaction and gene transfer with Fe-NPs) beneficial for CH4 production rate is provided. Microbial activity, inhibition effects and direct interspecies electron transfer through Fe-NPs have been extensively discussed. Finally, further studies towards detecting effective and optimised NPs based methods in the methanogenesis stage are reported.
  3. Amalina F, Krishnan S, Zularisam AW, Nasrullah M
    Sci Total Environ, 2024 Mar 01;914:169608.
    PMID: 38157898 DOI: 10.1016/j.scitotenv.2023.169608
    Employing biomass for environmental conservation is regarded as a successful and environmentally friendly technique since they are cost-effective, renewable, and abundant. Biochar (BC), a thermochemically converted biomass, has a considerably lower production cost than the other conventional activated carbons. This material's distinctive properties, including a high carbon content, good electrical conductivity (EC), high stability, and a large surface area, can be utilized in various research fields. BC is feasible as a renewable source for potential applications that may achieve a comprehensive economic niche. Despite being an inexpensive and environmentally sustainable product, research has indicated that pristine BC possesses restricted properties that prevent it from fulfilling the intended remediation objectives. Consequently, modifications must be made to BC to strengthen its physicochemical properties and, thereby, its efficacy in decontaminating the environment. Modified BC, an enhanced iteration of BC, has garnered considerable interest within academia. Many modification techniques have been suggested to augment BC's functionality, including its adsorption and immobilization reliability. Modified BC is overviewed in its production, functionality, applications, and regeneration. This work provides a holistic review of the recent advances in synthesizing modified BC through physical, chemical, or biological methods to achieve enhanced performance in a specific application, which has generated considerable research interest. Surface chemistry modifications require the initiation of surface functional groups, which can be accomplished through various techniques. Therefore, the fundamental objective of these modification techniques is to improve the efficacy of BC contaminant removal, typically through adjustments in its physical or chemical characteristics, including surface area or functionality. In addition, this article summarized and discussed the applications and related mechanisms of modified BC in environmental decontamination, focusing on applying it as an ideal adsorbent, soil amendment, catalyst, electrochemical device, and anaerobic digestion (AD) promoter. Current research trends, future directions, and academic demands were available in this study.
  4. Gupta N, Yadav KK, Kumar V, Krishnan S, Kumar S, Nejad ZD, et al.
    Environ Toxicol Pharmacol, 2021 Feb;82:103563.
    PMID: 33310081 DOI: 10.1016/j.etap.2020.103563
    This study determined the heavy metals (HMs) accumulation in different vegetables in different seasons and attributed a serious health hazard to human adults due to the consumption of such vegetables in Jhansi. The total amounts of zinc (Zn), lead (Pb), nickel (Ni), manganese (Mn), copper (Cu), cobalt (Co), and cadmium (Cd) were analysed in 28 composite samples of soil and vegetables (Fenugreek, spinach, eggplant, and chilli) collected from seven agricultural fields. The transfer factor (TF) of HMs from soil to analysed vegetables was calculated, and significant non-carcinogenic health risks due to exposure to analysed heavy metals via consumption of these vegetables were computed. The statistical analysis involving Principal Component Analysis (PCA) and Pearson's correlation matrix suggested that anthropogenic activities were a major source of HMs in the study areas. The target hazard quotient of Cd, Mn, and Pb for fenugreek (2.156, 2.143, and 2.228, respectively) and spinach (3.697, 3.509, 5.539, respectively) exceeded the unity, indicating the high possibilities of non-carcinogenic health risks if regularly consumed by human beings. This study strongly suggests the continuous monitoring of soil, irrigation water, and vegetables to prohibit excessive accumulation in the food chain.
  5. Zaied BK, Nasrullah M, Siddique MNI, Zularisam AW, Singh L, Krishnan S
    Sci Total Environ, 2020 Mar 01;706:136095.
    PMID: 31862587 DOI: 10.1016/j.scitotenv.2019.136095
    Lack of sufficient nitrogenous substrate and buffering potential have been acknowledged as impediments to the treatment of palm oil mill effluent through co-digestion processes. In this study, ammonium bicarbonate was used to provide the nitrogenous substrate and buffering potential. To regulate the impact of ammonium bicarbonate toxicity on the anaerobic co-digestion system, dosages from 0 to 40 mg/L were supplemented. The biogas yield was used to indicate the effects of NH4+ toxicity. In a solar-assisted bioreactor, solar radiation was first collected by a solar panel and converted into electricity, which was then used to heat a mixture of palm oil mill effluent and cattle manure to maintain the reactor in the mesophilic temperature range. This co-digestion operation was performed semi-continuously and was analyzed at a 50:50 mixing ratio of palm oil mill effluent and cattle manure. The results indicate that the additional dosing of ammonium bicarbonate can significantly enhance biogas production. Maximum cumulative biogas and methane productions of 2034.00 mL and 1430.51 mL, respectively, were obtained with the optimum addition of 10 mg/L ammonium bicarbonate; these values are 29.80% and 42.30% higher, respectively, than that obtained in the control co-digestion operation without addition of ammonium bicarbonate. Utilization of a mathematical equation (G = Gmk/t) to describe a kinetic analysis of the biogas yield also indicated that the optimum ammonium bicarbonate dose was 10 mg/L. The results of this study suggest that supplementation with ammonium bicarbonate doses of up to 40 mg/L can be used to provide nitrogenous substrates and buffering potential in anaerobic co-digestion processes. The determination of the optimal dose provides an alternative and efficient option for enhanced biogas production, which will have obvious economic advantages for feasible industrial applications.
  6. Jadhav P, Krishnan S, Kamyab H, Khalid ZB, Bhuyar P, Zularism AW, et al.
    Chemosphere, 2024 Jan;346:140512.
    PMID: 37879373 DOI: 10.1016/j.chemosphere.2023.140512
    The augmentation of biogas production can be achieved by incorporating metallic nanoparticles as additives within anaerobic digestion. The objective of this current study is to examine the synthesis of Fe-Ni-Zn and Fe-Co-Zn trimetallic nanoparticles using the co-precipitation technique and assess its impact on anaerobic digestion using palm oil mill effluent (POME) as carbon source. The structural morphology and size of the synthesised trimetallic nanoparticles were analysed using a range of characterization techniques, such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDX) . The average size of Fe-Ni-Zn and Fe-Co-Zn were 19-25.5 nm and 19.1-30.5 nm respectively. Further, investigation focused on examining the diverse concentrations of trimetallic nanoparticles, ranging from 0 to 50 mgL-1. The biogas production increased by 55.55% and 60.11% with Fe-Ni-Zn and Fe-Co-Zn trimetallic nanoparticles at 40 mgL-1 and 20 mgL-1, respectively. Moreover, the lowest biogas of 11.11% and 38.11% were found with 10 mgL-1 of Fe-Ni-Zn and Fe-Co-Zn trimetallic nanoparticles. The findings of this study indicated that the trimetallic nanoparticles exhibited interactions with anaerobes, thereby enhancing the degradation process of palm oil mill effluent (POME) and biogas production. The study underscores the potential efficacy of trimetallic nanoparticles as a viable supplement for the promotion of sustainable biogas generation.
  7. Krishnan S, Zulkapli NS, Din MFM, Majid ZA, Honda M, Ichikawa Y, et al.
    J Environ Manage, 2020 Feb 01;255:109890.
    PMID: 31790869 DOI: 10.1016/j.jenvman.2019.109890
    Water treatment plants generate vast amounts of sludge and its disposal is one of the most expensive and environmentally problematic challenges worldwide. As sludge from water treatment plants contains a considerable amount of titanium, both can create serious environmental concerns. In this study, the potential to recover titanium from drinking water treatment residue was explored through acid leaching technique. Statistical design for the optimization of titanium recovery was proposed using response surface methodology (RSM) based on a five-level central composite design (CCD). Three independent variables were investigated, namely the acid concentration (3 M-7 M), temperature (40 °C - 80 °C) and solid/liquid ratio (0.005-0.02 g/mL). According to the analysis of variance (ANOVA), the p-value (<0.0001) indicated the designed model was highly significant. Optimization using RSM gave the best fit between validated and predicted data as elucidated by the coefficient of determination with R2 values of 0.9965. However, acid concentration and solid/liquid ratio showed an initial increase in titanium recovery followed by recovery reduction with increasing concentration and ratio. Quadratic RSM predicted the maximum recovery of titanium to be 67.73% at optimal conditions of 5.5 M acid concentration, at a temperature of 62 °C with a solid/liquid ratio of 0.01 g/mL. The verification experiments gave an average of 66.23% recovery of titanium, thus indicating that the successfully developed model to predict the response. This process development has significant importance to reduce the cost of waste disposal, environmental protection, and recovery of economically valuable products.
  8. Moideen SNF, Krishnan S, Li YY, Hassim MH, Kamyab H, Nasrullah M, et al.
    Chemosphere, 2023 Mar;317:137923.
    PMID: 36682635 DOI: 10.1016/j.chemosphere.2023.137923
    An anaerobic membrane bioreactor (AnMBR) was employed as primary treatment unit for anaerobic treatment of simulated wastewater to produce high effluent quality. A lab scale hollow fiber membrane was used to scrutinize the performance of AnMBR as a potential treatment system for simulated milk wastewater and analyze its energy recovery potential. The 15 L bioreactor was operated continuously at mesophilic conditions (35 °C) with a pH constant of 7.0. The membrane flux was in the range of 9.6-12.6 L/m2. h. The different organic loading rates (OLRs) of 1.61, 3.28, 5.01, and 8.38 g-COD/L/d, of simulated milk wastewater, were fed to the reactor and the biogas production rate was analyzed, respectively. The results revealed that the COD removal efficiencies of 99.54 ± 0.001% were achieved at the OLR of 5.01 gCOD/L/d. The highest methane yield was found to be at OLR of 1.61 gCOD/L/d at HRT of 30 d with the value of 0.33 ± 0.01 L-CH4/gCOD. Moreover, based on the analysis of energy balance in the AnMBR system, it was found that energy is positive at all the given HRTs. The net energy production (NEP) ranged from 2.594 to 3.268 kJ/gCOD, with a maximum NEP value of 3.268 kJ/gCOD at HRT 10 d HRT. Bioenergy recovery with the maximum energy ratio, of 4.237, was achieved with an HRT of 5 d. The study suggests a sizable energy saving with the anaerobic membrane process.
  9. Mazlan D, Krishnan S, Din MFM, Tokoro C, Khalid NHA, Ibrahim IS, et al.
    Sci Rep, 2020 04 14;10(1):6412.
    PMID: 32286486 DOI: 10.1038/s41598-020-63575-7
    This paper aims to examine the effect of cellulose nanocrystals (CNCs) derived from oil palm empty fruit bunch fiber (EFB) incorporating cement mortar on its structural performances. Cellulose nanocrystals (CNCs) were extracted from α-cellulose extracted from EFB using an acid hydrolysis process with a concentration of acid used was 64% w/v under the temperature of 45 °C for 60 minutes. The Cellulose nanocrystals (CNCs) were mixed into the cement mortar ranging from 0 to 0.8% w/w and its mechanical properties were determined. The developed CNCs mortar was characterized for their compressive and flexural properties as well as microstructure. The influence of CNCs concentration, curing method, dispersion of CNCs on mortar's mechanical performance was thoroughly examined to find out the optimum condition. Overall results revealed that an addition of 0.4% cellulose nanocrystals has shown to increase the compressive and flexural strength to 46% and 20%, respectively cured under the wrapping method. The hydration of cementitious composites also improved significantly with the addition of CNCs by the formation of highly crystalline of portlandite observed under the XRD test. This present work demonstrates the importance of palm oil empty fruit bunch waste as a sustainable resource of cellulose nanocrystals admixture to achieve structural strength of cement mortar and promotes green technologies in construction.
  10. Krishnan S, Suzana BN, Wahid ZA, Nasrullah M, Abdul Munaim MS, Din MFBM, et al.
    Biotechnol Rep (Amst), 2020 Sep;27:e00498.
    PMID: 32670809 DOI: 10.1016/j.btre.2020.e00498
    The application of the xylose reductase (XR) enzyme in the development of biotechnology demands an efficient and large scale enzyme separation technique. The aim of this present work was to optimize xylose reductase (XR) purification process through ultrafiltration membrane (UF) technology using Central composite design (CCD) of response surface methods (RSM). The three effective parameters analyzed were filtration time (0-100), transmembrane pressure (TMP) (1-1.6 bar), cross flow velocity (CFV) (0.52-1.2 cm/s-1) and its combined effect to obtain high flux with less possibility of membrane fouling. Experimental studies revealed that the best range for optimization process for filtration time, operational transmembrane pressure and cross flow velocity was 30 min, 1.4 bars and 1.06 cm/s, respectively as these conditions yielded the highest membrane permeability (56.03 Lm-2h-1 bar-1) and xylitol content (15.49 g/l). According to the analysis of variance (ANOVA), the p-value (<0.0001) indicated the designed model was highly significant. The error percentage between the actual and predicted value for membrane permeability and xylitol amount (2.21 % and 4.85 % respectively), which both were found to be close to the predicted values. The verification experiments gave membrane actual permeability of 57.3 Lm-2h-1 bar-1 and 16.29 g/l of xylitol production, thus indicating that the successfully developed model to predict the response.
  11. Adelodun B, Kareem KY, Kumar P, Kumar V, Choi KS, Yadav KK, et al.
    J Clean Prod, 2021 Oct 10;318:128451.
    PMID: 36570877 DOI: 10.1016/j.jclepro.2021.128451
    The existing finite natural resources have witnessed unsustainable usage in the past few years, especially for food production, with accompanying environmental devastation and ecosystem damage. Regrettably, the global population and consumption demands are increasing ceaselessly, leading to the need for more resources for food production, which could potentially aggravate the sustainability and ecosystem degradation issues, while stimulating drastic climate change. Meanwhile, the unexpected emergence of the COVID-19 pandemic and some implemented measures to combat its spread disrupted agricultural activities and the food supply chain, which also led to a reduction in ecosystem carbonization. This study sets out to explore policy framework and selected feasible actions that are being adopted during the COVID-19 pandemic, which could potentially reduce the emissions even after the pandemic to promote a resilient and sustainable agri-food system. In this study, we reviewed 27 articles that focus on the current state of the agri-food system in light of the COVID-19 pandemic and its impact on the decarbonization of the agroecosystem. This review has taken the form of a systematic methodology in analyzing the adoption and implementation of various measures to mitigate the spread of COVID-19 on the impact of the agri-food system and reduction in ecosystem degradation. Up to 0.3 Mt of CO2 reduction from the agri-food system alone was reportedly achieved during the first 6 months of the pandemic in 23 European countries. The various adopted measures indicate that the circular economy approach is a panacea to achieve the needed sustainability in the agri-food system. Also, it dictates a need for a paradigm change towards improvement on localized food production that promotes sustainable production and consumption.
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