CELL GROWTH KINETICS OF ASPERGILLUS ORYZAE IN INDUSTRIAL NATURAL RUBBER EFFLUENT SERUM

ABSTRACT A dynamic relationship exists between environmental conditions and the growth pattern of filamentous fungi. Growth kinetics such as the relationship between specific growth rate and the concentration of a substrate is one of the basic tools in microbiology. In such cases, a direct monitoring of the cell morphology and biomass distribution in the culture medium is potential. Hence the present work attempt to study the nutrient uptake and cell growth kinetics of a nonpathogenic fungus Aspergillus oryzae possessing the ability of bioremediation in the wasteful industrial rubber effluent. Four different models of Monod, Contois, Verhulst, and Tessier were used to investigate the cell growth kinetics in batch submerged fermentation process carried out in shake flasks. The compatibility of the experimental data fitted with Contois, Verhulst and Tessier models with the regression values are 0.65, 0.80, 0.21 and 0.84 respectively. Although Verhulst and Contois are the most suitable kinetic models to describe substrate utilization and cell growth behavior of filamentous fungi in submerged culture, the Tessier model was found best fitted with the experimental data. In the case of Monod, the maximum specific growth rate, µm and the half saturation constant, Ks were determined as 2.3 day -1 and 4.84 g/l respectively. For Verhulst, the maximum specific growth rate, µm and maximum biomass, Xm in terms of cell dry weight were determined as 0.9 day -

Naturally acquired antibody response to Plasmodium falciparum and Plasmodium vivax among indigenous Orang Asli communities in Peninsular Malaysia

Malaria remains a public health problem in many parts of the world. In Malaysia, the significant progress towards the national elimination programme and effective disease notification on malaria has resulted in zero indigenous human malaria cases since 2018. However, the country still needs to determine the extent of malaria exposure and transmission patterns, particularly in high-risk populations. In this study, a serological method was used to measure transmission levels of Plasmodium falciparum and Plasmodium vivax among indigenous Orang Asli communities in Kelantan, Peninsular Malaysia. A community-based cross-sectional survey was conducted in three Orang Asli communities (i.e., Pos Bihai, Pos Gob, and Pos Kuala Betis) in Kelantan from June to July 2019. Antibody responses to malaria were assessed by enzyme-linked immunosorbent assay (ELISA) using two P. falciparum (PfAMA-1 and PfMSP-119) and two P. vivax (PvAMA-1 and PvMSP-119) antigens. Age-adjusted antibody responses were analysed using a reversible catalytic model to calculate seroconversion rates (SCRs). Multiple logistic regression was used to investigate factors associated with malaria exposure. The overall malaria seroprevalence was 38.8% for PfAMA-1, 36.4% for PfMSP-119, 2.2% for PvAMA-1, and 9.3% for PvMSP-119. Between study areas, the proportion of seropositivity for any P. falciparum and P. vivax antigens was significantly highest in Pos Kuala Betis with 34.7% (p < 0.001) and 13.6% (p < 0.001), respectively. For all parasite antigens except for PvAMA-1, the proportion of seropositive individuals significantly increased with age (all p < 0.001). Based on the SCR, there was a higher level of P. falciparum transmission than P. vivax in the study area. Multivariate regression analyses showed that living in Pos Kuala Betis was associated with both P. falciparum (adjusted odds ratio [aOR] 5.6, p < 0.001) and P. vivax (aOR 2.1, p < 0.001) seropositivities. Significant associations were also found between age and seropositivity to P. falciparum and P. vivax antigens. Analysis of community-based serological data helps describe the level of transmission, heterogeneity, and factors associated with malaria exposure among indigenous communities in Peninsular Malaysia. This approach could be an important adjunct tool for malaria monitoring and surveillance in low malaria transmission settings in the country

Evidence of Submicroscopic Plasmodium knowlesi Mono-Infection in Remote Indigenous Communities in Kelantan, Peninsular Malaysia

Malaysia has maintained zero cases of indigenous human malaria since 2018. However, zoonotic malaria is still prevalent in underdeveloped areas and hard-to-reach populations. This study aimed to determine the prevalence of malaria among remote indigenous communities in Peninsular Malaysia. A cross-sectional survey was conducted in six settlements in Kelantan state, from June to October 2019. Blood samples were tested for malaria using microscopy and nested polymerase chain reaction (nPCR) targeting the Plasmodium cytochrome c oxidase subunit III (cox3) gene. Of the 1,954 individuals who appeared healthy, no malaria parasites were found using microscopy. However, nPCR revealed seven cases of Plasmodium knowlesi mono-infection (0.4%), and six out of seven infections were in the group of 19 to 40 years old (P = 0.026). No human malaria species were detected by nPCR. Analysis of the DNA sequences also showed high similarity that reflects common ancestry to other P. knowlesi isolates. These findings indicate low submicroscopic P. knowlesi infections among indigenous communities in Malaysia, requiring PCR-based surveillance to support malaria control activities in the country

Effect of different media components and process conditions on the productivity of phenolic compounds from palm oil mill effluent by local isolated strain

The present investigation is an effort to develop an environmentally sound and cost effective fermentation process by introducing a new potential strain of Aspergillus niger which was isolated locally for the production of phenolics from palm oil mill effluent (POME). The selection of the potential fungal strain was done previously by screening seven strains and strain A103, which gave the highest total phenolic content after 72 hours of fermentation at fixed media and process conditions was used in this study. To enhance the production of phenolic compounds, a study based on statistical design was employed. A two-level Plackett-Burman design was applied where 11 variables consisted of various media components and process conditions were studied for their influence on phenolics production. Out of 11 variables, sucrose, manganese sulfate (MnSO4), and temperature were identified as the most significant variables in improving phenolics production by A103 strain. Single factor optimization for the selected variables was performed to further the optimization for the phenolics production. After the optimization, total phenolic content increased significantly from 856.09 to 940.80 GAE mg/l. The optimum conditions were found at a temperature of 35.0°C, 6.0% (w/v) sucrose, and 2.5% (w/v) MnSO4, with other fixed parameters. Surprisingly, the scavenging activity of the fermented extract on 2,2-diphenyl-1- picrylhydrazyl (DPPH) radical showed almost 95% of inhibition. The activity was higher compared to butylated hydroxytoluene (BHT), a synthetic antioxidant which showed only 91% of inhibition, with promising applications in food and pharmaceutical industries

Evaluation of Palm Oil Mill Effluent Treatment Concomitant Phenolics Production by Aspergillus Niger IBS-103ZA

Previous results show that fermentation of palm oil mill effluent (POME) with Aspergillus niger IBS-103ZA has successfully increased the phenolic content and also antioxidant activities of the extract [1]. In this study, the potential use of Aspergillus niger IBS-103ZA to treat the effluent for removal of chemical oxygen demand (COD) and heavy metals were evaluated. The percentage of COD removal was very low. Only 24.44% of COD was removed after 120 hours of fermentation period. Aspergillus niger IBS-103ZA biomass absorbed Pb2+ ions from POME more rapidly than Zn2+ ions. Within 24 hours of fermentation period, the percentage removal of Pb2+ ions was 76.08%. The Pb2+ ions were totally removed after 72 hours of fermentation period. The removal of Zn2+ ions from POME was not as efficient as Pb2+ ions. Only 24.79% of Zn2+ ions were removed after 120 hours of fermentation period. No Cd was detected in POME during the study. Thus, treating POME via fermentation with Aspergillus niger IBS-103ZA not only increases its value added product but also reduces the pollution load in the effluent

Evaluation of palm oil mill effluent treatment with concomitant phenolics production by aspergillus niger IBS-103ZA

Previous results show that fermentation of palm oil mill effluent (POME) with Aspergillus niger IBS-103ZA has successfully increased the phenolic content (from 856±2.22 to 941±3.72 GAE mg/l) and also antioxidant activity of the extract (with IC50 value of 0.45 mg/ml compared to unfermented extract with IC50 value of 1.13 mg/ml based on DPPH radical scavenging assay). In this study, the potential use of Aspergillus niger IBS-103ZA to treat the effluent for removal of chemical oxygen demand (COD) and heavy metals were evaluated. The percentage of COD removal was low. Only 24.44% of COD was removed after 120 hours of fermentation period. The biomass of Aspergillus niger IBS-103ZA absorbed Pb2+ ions from POME more rapidly than Zn2+ ions. Within 24 hours of fermentation period, the percentage removal of Pb2+ ions was 76.08%. The Pb2+ ions were totally removed after 72 hours of fermentation period. The removal of Zn2+ ions from POME was not as efficient as Pb2+ ions. Only 24.79% of Zn2+ ions were removed after 120 hours of fermentation period. No Cd was detected in POME during the study. The highest phenolics production (949.56±3.82 GAE mg/l) and total protein (76.58±0.43 g/kg-dried biomass) were obtained at 72 and 48 hours of fermentation respectively. Thus, POME treatment via fermentation with Aspergillus niger IBS-103ZA not only increased the amount of its value added product but also reduced the pollution load in the effluent

Effects of physicochemical parameters on the production of phenolic acids from palm oil mill effluent under liquid-state fermentation by Aspergillus niger IBS-103ZA

The present investigation is an effort to develop an environmentally friendly and cost-effective liquid-state fermentation process by introducing a new locally isolated fungal strain of Aspergillus niger (IBS-103ZA) for the production of phenolics from a new source, palm oil mill effluent (POME). Sucrose, manganese sulphate (MnSO4) and temperature were identified as the most significant variables in improving phenolics production. Optimisation increased the total phenolic content from 856 ± 2.22 to 941 ± 3.72 GAE mg/l at 35.0 °C, 6.0% (w/v) sucrose, 2.7% (w/v) MnSO4, and with other parameters fixed. The fermented extract (FE) with IC50 value of 0.45 mg/ml showed the strongest antioxidant potency, compared to unfermented extract (UFE), with IC50 of 1.13 mg/ml, and the synthetic antioxidant, BHT, with IC50 of 0.63 mg/ml. The phenolic compounds were identified and quantified by HPLC

Adsorption and desorption kinetic studies of bioactive phenolics purification on selected macroporous resins

In this study, two different types of macroporous resins known as XAD-7HP and HP-20 were evaluated for the adsorption and desorption properties against bioactive phenolics extracted from Phanerochaete chrysosporium. The study was conducted at different phase contact time, solution pH and ethanol concentration by static adsorption and desorption methods. From the results, it was found that the adsorption capacity for both resins has no significant difference. Meanwhile in desorption study, HP-20 and XAD-7HP gave 90.52% and 88.28% recoveries, respectively. Then, the kinetic adsorption data were analyzed with both pseudo-first-order and pseudo-second-order equations and the later performed better. The adsorption isotherm data were fitted well by both Langmuir and Freundlich models