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Time-based changes in authorship trend in research-intensive universities in Malaysia

Abu Kassim NL, Mohd Bakri SK, Nusrat F, Salim E, Manjurul Karim M, Rahman MT

Account Res, 2024 Dec;31(1):56-71.
PMID: 35758245 DOI: 10.1080/08989621.2022.2094256

Considering the fact that publications serve as an important criterion to evaluate the scientific accomplishments of an individual within respective fields in academia, there has been an increasing trend to publish scientific articles whereby multiple authors are defined as primary, co-, or corresponding authors according to the roles performed. This article analyzes the authorship pattern in 4,561 papers (including 60 single-authored papers) from 1990 till 2020 of 94 academics who hold a position as professors and are affiliated with the Faculty of Medicine at three different research universities in Malaysia. Only 708 papers (15.5% of 4,561 papers) were authored by less than three authors. In 3,080 papers (67.5% of 4,561 papers), those academics appeared as coauthors. Using different years as cutoff periods, it was observed that the appearance as coauthor in the papers had steeply risen around the years: 2006, 2007, 2008 and onwards. The increased number of authors in the multi-author papers and the appearance of the selected academics as coauthors reflect the extent of boosting of collaborative research in that period which corresponds to the adoption of the "publish or perish policy" by the Ministry of Higher Education in Malaysia.
Fulltext The values of the traditional culinary practices towards the modernization as perceived by the Malay Chefs in Klang Valley

Ismail, N. A., Ab. Karim, M. S., Othman, M., Abd. Halim, N.

International Food Research Journal, 2013;20(5):0-0.
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The central question to be examined in this study is associated with the value of the Malays traditional culinary practices of Malay chef in preparing the traditional food in Malaysian hotels. Present understanding highlighted that hotels are giving high priority on their superior services, such as luxury accommodations and intimate hospitalities. As such, promoting local foods in their dining establishment has taken a back seat. Research from past scholars indicated that hotel in Malaysia can be the one stop center for the local and international tourists to get the first hand information about local food specialities. On the hindsight, very limited efforts have been put into practice on the promotions of local food especially Malay cuisines in hotels. Main issue such as mass-produced Malay cuisines in the commercial kitchens, for example, should be highlighted to ensure that hotels are not jeopardizing the originality of traditional food preparations. Therefore, a qualitative reasearch focusing in in-depth interview with 10 Malay chefs was conducted in hotels around the Klang Valley. The results are so profound that majority of the Malay chefs under study shared similar understandings on technology advancements and modernizations that have taken place in their daily food preparations. Another finding revealed that one of the most challenging factors in preventing the Malay chefs to prepare the Malay food as it has been done traditionally is the attitude and awareness of the young generations to understand the values in traditional culinary practices. This study concludes with suggestion that aggressive knowledge sharing and information dissemination among the Malay chefs in hotels are needed to effectively market the traditional Malay food.
The effects of mis-centering on radiation dose during CT head examination: A phantom study

Isa INC, Rahmat SMS, Dom SM, Kayun Z, Karim MKA

J Xray Sci Technol, 2019;27(4):631-639.
PMID: 31205011 DOI: 10.3233/XST-190491

There are several factors that may contribute to the increase in radiation dose of CT including the use of unoptimized protocols and improper scanning technique. In this study, we aim to determine significant impact on radiation dose as a result of mis-centering during CT head examination. The scanning was performed by using Toshiba Aquilion 64 slices multi-detector CT (MDCT) scanner and dose were measured by using calibrated ionization chamber. Two scanning protocols of routine CT head; 120 kVp/ 180 mAs and 100 kVp/ 142 mAs were used represent standard and low dose, respectively. As reference measurement, the dose was first measured on standard cylindrical polymethyl methacrylate (PMMA) phantom that positioned at 104 cm from the floor (reference isocenter). The positions then were varied to simulate mis-centering by 5 cm from isocenter, superiorly and inferiorly at 109 cm, 114 cm, 119 cm, 124 cm and 99 cm, 94 cm, 89 cm, 84 cm, respectively. Scanning parameter and dose information from the console were recorded for the radiation effective dose (E) measurement. The highest mean CTDIvol value for MCS and MCI were 105.06 mGy (at +10 cm) and 105.51 mGy (at - 10 cm), respectively which differed significantly (p
The effectiveness of bismuth breast shielding with protocol optimization in CT Thorax examination

Karim MKA, Rahim NA, Matsubara K, Hashim S, Mhareb MHA, Musa Y

J Xray Sci Technol, 2019;27(1):139-147.
PMID: 30584178 DOI: 10.3233/XST-180397

BACKGROUND: Numerous techniques had been proposed to reduce radiation exposure in computed tomography (CT) including the use of radiation shielding.
OBJECTIVE: This study aims to evaluate efficacy of using a bismuth breast shield and optimized scanning parameter to reduce breast absorbed doses from CT thorax examination.
METHODS: Five protocols comprising the standard CT thorax clinical protocol (CP1) and four modified protocols (CP2 to CP5) were applied in anthropomorphic phantom scans. The phantom was configured as a female by placing a breast component on the chest. The breast component was divided into four quadrants, where 2 thermoluminescence dosimeters (TLD-100) were inserted into each quadrant to measure the absorbed dose. The bismuth shield was placed over the breast component during CP4 and CP5 scans.
RESULTS: The pattern of absorbed doses in each breast and quadrant were approximately the same for all protocols, where the 4th quadrant > 3rd quadrant > 2nd quadrant > 1st quadrant. The mean absorbed dose value in CP3 was reduced to almost 34% of CP1's mean absorbed dose. It was reduced even lower to 15% of CP1's mean absorbed dose when the breast shield was used in CP5.
CONCLUSION: This study showed that CT radiation exposure on the breast could be reduced by using a bismuth shield and low tube potential protocol without compromising the image quality.
Fulltext The Efficacy of Moina micrura Enriched with Probiotic Bacillus pocheonensis in Enhancing Survival and Disease Resistance of Red Hybrid Tilapia (Oreochromis spp.) Larvae

Samat NA, Yusoff FM, Rasdi NW, Karim M

Antibiotics (Basel), 2021 Aug 16;10(8).
PMID: 34439039 DOI: 10.3390/antibiotics10080989

The administration of probiotics via live feeds, such as Artemia and rotifers, has gained significant attention. Moreover, indiscriminate use of antibiotics in conventional aquaculture practices in order to prevent or control disease outbreaks has resulted in the occurrence of residues and antimicrobial resistance. Thus, the application of eco-friendly feed additives, such as probiotics, as a safer alternative has received increasing attention in recent years. However, only minimal information on the administration of probiotics via freshwater cladoceran Moina micrura is available despite being commonly used for larval and post-larval feeding of freshwater crustaceans and fish. Thus, this study aimed to evaluate the application of Bacillus pocheonensis strain S2 administered via M. micrura to red hybrid tilapia (Oreochromis spp.) larvae. Bacillus pocheonensis that has been previously isolated from Spirulina sp. was subjected to preliminary in vitro evaluation of antagonistic properties. The agar well-diffusion assay revealed that this probiont could inhibit the growth of Streptococcus agalactiae and Aeromonas hydrophila. The size of inhibition zones ranged from 8.8 ± 0.2 to 18.2 ± 0.4 mm. Moina micrura was later used as a biological model in preliminary in vivo bacterial challenge assays to evaluate the efficacy of B. pocheonensis in protecting the host from diseases. Moina micrura was pre-enriched with B. pocheonensis at 104 and 106 CFU mL-1 before S. agalactiae and A. hydrophila were introduced into the culture. The study revealed that B. pocheonensis at 104 CFU mL-1 was able to significantly enhance the survival of M. micrura after being challenged with both pathogens (63 ± 3%) in comparison to the control group. The relative percentage survival (RPS) of M. micrura was highest (p < 0.05) when treated with B. pocheonensis at both concentrations 104 and 106 CFU mL-1 (38.33) after being challenged against S. agalactiae. To assess the efficacy of B. pocheonensis in protecting red hybrid tilapia against streptococcosis, the larvae were fed with either unenriched (control) Moina or probiont-enriched Moina daily for 10 days. A significantly (p < 0.05) higher survival rate (77 ± 3%) was observed in larvae fed with probiont-enriched M. micrura compared to other treatments, and the RPS was recorded at 62.90. In addition, the S. agalactiae load was suppressed in larvae fed probiont-enriched M. micrura (6.84±0.39 CFU mL-1) in comparison to the control group (7.78±0.09 CFU mL-1), indicating that the probiont might have contributed to the improvement of tilapia health and survival. This study illustrated that M. micrura was suitable to be used as a vector for probiotics in freshwater fish larvae as an alternative to hazardous antibiotics for disease control.
Review on diagnosis and molecular characterization of Toxoplasma gondii in humans and animals

Uddin AHMM, Hossain D, Ahsan MI, Atikuzzaman M, Karim MR

Trop Biomed, 2021 Dec 01;38(4):511-539.
PMID: 35001919 DOI: 10.47665/tb.38.4.091

Toxoplasma gondii is an obligate intracellular protozoon which causes toxoplasmosis, an important zoonotic disease that is endemic worldwide. Common sources of T. gondii infection in humans are food or water contaminated with oocysts and raw or undercooked meat with cysts. In animals, common sources of infection include feed, water, or litter contaminated with oocysts. The diagnosis and molecular characterization of T. gondii infection in humans and animals is crucial due to public and veterinary health importance. Various traditional and serological methods have been used in clinical practice for toxoplasmosis diagnosis, but interpreting the results remains a challenge. Several molecular techniques have also been used for the detection and genetic characterization of T. gondii , but primarily in research settings. In this paper, we review the techniques that are currently used for the diagnosis and genetic characterization of T. gondii in humans and animals, along with their advantages and disadvantages. The techniques reviewed have laid the groundwork for the future development of more effective and precise detection and characterization of T. gondii . These advances will contribute to a better understanding of epidemiology, prevention and control of toxoplasmosis. Thus, this review would be of particular interest to clinical physicians, veterinarians and researchers.
Quorum sensing is required for full virulence of Vibrio campbellii towards tiger grouper (Epinephelus fuscoguttatus) larvae

Noor NM, Defoirdt T, Alipiah N, Karim M, Daud H, Natrah I

J Fish Dis, 2019 Apr;42(4):489-495.
PMID: 30742313 DOI: 10.1111/jfd.12946

The link between quorum sensing in Vibrio campbellii and its virulence towards tiger grouper (Epinephelus fuscoguttatus) was investigated using V. campbellii wild type and quorum-sensing mutants with inactive quorum sensing or constitutively maximal quorum-sensing activity, and signal molecule synthase mutants. The results showed that wild-type V. campbellii is pathogenic to grouper larvae, causing more than 50% mortality after 4 days of challenge. Furthermore, the mortality of larvae challenged with the mutant with maximally active quorum sensing was significantly higher than that of larvae challenged with the wild type, whereas a higher survival was observed in the larvae challenged to the mutant with a completely inactive quorum-sensing system. Grouper larvae challenged with either the signal molecule synthase triple mutant, the harveyi autoinducer-1 (HAI-1) synthase mutant and the autoinducer-2 (AI-2) synthase mutant showed higher survival than larvae challenged with the wild type. In contrast, larvae challenged with the cholerae autoinducer-1 (CAI-1) synthase mutant showed high mortality. This indicates that HAI-1 and AI-2, but not CAI-1, are required for full virulence of V. campbellii towards grouper larvae. Our data suggest that quorum-sensing inhibition could be an effective strategy to control V. campbellii infections in tiger grouper.
Production of xylose from Meranti wood sawdust by dilute acid hydrolysis

Rafiqul IS, Sakinah AM, Karim MR

Appl Biochem Biotechnol, 2014 Sep;174(2):542-55.
PMID: 25082763 DOI: 10.1007/s12010-014-1059-z

Xylitol production by bioconversion of xylose can be economically interesting if the raw material can be recovered from a cheap lignocellulosic biomass (LCB). Meranti wood sawdust (MWS) is a renewable and low-cost LCB that can be used as a promising and economic source of xylose, a starting raw material for the manufacture of several specialty chemicals, especially xylitol. This study aimed to optimize the hydrolysis process of MWS and to determine the influence of temperature, H2SO4 concentration, and residence time on xylose release and on by-product formation (glucose, arabinose, acetic acid, furfural, hydroxymethylfurfural (HMF), and lignin degradation products (LDPs)). Batch hydrolysis was conducted under various operating conditions, and response surface methodology was adopted to achieve the highest xylose yield. Xylose production was highly affected by temperature, acid concentration, and residence time. The optimum temperature, acid concentration, and time were determined to be 124 °C, 3.26 %, and 80 min, respectively. Under these optimum conditions, xylose yield and selectivity were attained at 90.6 % and 4.05 g/g, respectively.
Production of organic acids from kitchen wastes

Loh CW, Fakhru'l-Razi A, Hassan MA, Karim MI

Artif Cells Blood Substit Immobil Biotechnol, 1999 Sep-Nov;27(5-6):455-9.
PMID: 10595448

This study involves the production of short-chain organic acids from kitchen wastes as intermediates for the production of biodegradable plastics. Flasks, without mixing were used for the anaerobic conversion of the organic fraction of kitchen wastes into short-chain organic acids. The influence of pH, temperature and addition of sludge cake on the rate of organic acids production and yield were evaluated. Fermentations were carried out in an incubator at different temperatures controlled at 30 degrees C. 40 degrees C, 50 degrees C, 60 degrees C and uncontrolled at room temperature. The pH was also varied at pH 5, 6, 7, and uncontrolled pH. 1.0 M phosphate buffer was used for pH control, and 1.0 M HCl and 1.0 M NaOH were added when necessary. Sludge cake addition enhanced the rate of maximum acids production from 4 days to 1 day. The organic acids produced were maximum at pH 7 and 50 degrees C i.e., 39.84 g/l on the fourth day of fermentation with a yield of 0.87 g/g soluble COD consumed, and 0.84 g/g TVS. The main organic acid produced was lactic acid (65-85%), with small amounts of acetic (10-30%), propionic (5-10%), and butyric (5-20%) acids. The results of this study showed that kitchen wastes could be fermented to high concentration of organic acids, which could be used as substrates for the production of biodegradable plastics.
New method for distance-based close following safety indicator

Sharizli AA, Rahizar R, Karim MR, Saifizul AA

Traffic Inj Prev, 2015;16(2):190-5.
PMID: 24827899 DOI: 10.1080/15389588.2014.921913

The increase in the number of fatalities caused by road accidents involving heavy vehicles every year has raised the level of concern and awareness on road safety in developing countries like Malaysia. Changes in the vehicle dynamic characteristics such as gross vehicle weight, travel speed, and vehicle classification will affect a heavy vehicle's braking performance and its ability to stop safely in emergency situations. As such, the aim of this study is to establish a more realistic new distance-based safety indicator called the minimum safe distance gap (MSDG), which incorporates vehicle classification (VC), speed, and gross vehicle weight (GVW).
Kojic acid production by Aspergillus flavus using gelatinized and hydrolyzed sago starch as carbon sources

Rosfarizan M, Ariff AB, Hassan MA, Karim MI

Folia Microbiol (Praha), 1998;43(5):459-64.
PMID: 9867479

Direct conversion of gelatinized sago starch into kojic acid by Aspergillus flavus strain having amylolytic enzymes was carried out at two different scales of submerged batch fermentation in a 250-mL shake flask and in a 50-L stirred-tank fermentor. For comparison, fermentations were also carried out using glucose and glucose hydrolyzate from enzymic hydrolysis of sago starch as carbon sources. During kojic acid fermentation of starch, starch was first hydrolyzed to glucose by the action of alpha-amylase and glucoamylase during active growth phase. The glucose remaining during the production phase (non-growing phase) was then converted to kojic acid. Kojic acid production (23.5 g/L) using 100 g/L sago starch in a shake flask was comparable to fermentation of glucose (31.5 g/L) and glucose hydrolyzate (27.9 g/L) but in the 50-L fermentor was greatly reduced due to non-optimal aeration conditions. Kojic acid production using glucose was higher in the 50-L fermentor than in the shake flask.
Isolation of verotoxin-producing Escherichia coli associated with diarrhoea in Malaysia containing plasmids showing homology with biotinylated Shiga-like toxin DNA gene probes

Son R, Ansary A, Rusul G, Karim MI

World J Microbiol Biotechnol, 1996 May;12(3):243-6.
PMID: 24415231 DOI: 10.1007/BF00360921

Three strains of verotoxin-producing Escherichia coli isolated from patients with haemorrhagic colitis harboured plasmids ranging in size from 2.7 kb to 91.2 kb. Those plasmids ranging from 2.7 kb to 6.8 kb hybridized to Shiga-like toxin I and Shiga-like toxin II gene probes.
Influence of Symbiotic Probiont Strains on the Growth of Amphora and Chlorella and Its Potential Protections Against Vibrio spp. in Artemia

Rosland NA, Ikhsan N, Min CC, Yusoff FM, Karim M

Curr Microbiol, 2021 Nov;78(11):3901-3912.
PMID: 34522979 DOI: 10.1007/s00284-021-02642-2

The emerging aquaculture industry is in need of non-antibiotic-based disease control approaches to minimize the risk of antibiotic-resistant bacteria. Bacterial infections mainly caused by Vibrio spp. have caused mass mortalities of fish especially during the larval stages. The objectives of this study were to verify the potential of symbiotic probiont strains, isolated from microalgae (Amphora, Chlorella, and Spirulina) for suppressing the growth of Vibrio spp. and at the same time ascertain their abilities to enhance microalgal biomass by mutualistic interactions through microalgae-bacteria symbiosis. In addition, in vivo studies on Artemia bioencapsulated with probiont strains (single strain and mix strains) and microalgae were evaluated. The selected potential probionts were identified as Lysinibacillus fusiformis strain A-1 (LFA-1), Bacillus sp. strain A-2 (BA-2), Lysinibacillus fusiformis strain Cl-3 (LFCl-3), and Bacillus pocheonensis strain S-2 (BPS-2) using 16s rRNA. The cell densities of Amphora culture supplemented with BA-2 and Chlorella culture supplemented with LFCl-3 were higher than those of the controls. Artemia bioencapsulated with mix strains (LFA-1 + BA-2 + LFCl-3 + BPS-2) and Amphora demonstrated the highest survival rate compared to the controls, after being challenged with V. harveyi (60 ± 4%) and V. parahaemolyticus (78 ± 2%). Our study postulated that BA-2 and LFCl-3 were found to be good promoting bacteria for microalgal growth and microalgae serve as a vector to transport probiotic into Artemia. Moreover, mixture of potential probionts is beneficial for Artemia supplementation in conferring protection to Artemia nauplii against pathogenic Vibrios.
How low back pain is managed-a mixed methods study in 32 countries. Part 2 of Low Back Pain in Low- and Middle-Income Countries Series

Sharma S, Pathak A, Parker R, Costa LOP, Ghai B, Igwesi-Chidobe C, et al.

J Orthop Sports Phys Ther, 2024 Apr 11.
PMID: 38602844 DOI: 10.2519/jospt.2024.12406

BACKGROUND: The Lancet Series of Low Back Pain (LBP) highlighted the lack of LBP data from low- and middle-income countries (LMICs). The study aimed to describe (1) what LBP care is currently delivered in LMICs, and (2) how that care is delivered. METHODS: An online mixed-methods study. A Consortium for LBP in LMICs (n=65) was developed with an expert panel of leading LBP researchers (>2 publications on LBP) and multidisciplinary clinicians and patient partners with five years of clinical/lived LBP experience in LMICs. Quantitative data were analyzed using descriptive statistics. Two researchers independently analyzed qualitative data using deductive and inductive coding and developed a thematic framework. FINDINGS: Forty-seven (85%) of 55 invited panel members representing 32 LMICs completed the survey (38% women; 62% men). The panel included clinicians (34%), researchers (28%), educators (6%), and patient partners (4%). Pharmacotherapies and electrophysiological agents were the most used LBP treatments. The Thematic Framework comprised of eight themes: (1) Self-management is ubiquitous; (2) Medicines are the cornerstone; (3) Traditional therapies have a place; (4) Society plays an important role; (5) Imaging use is very common; (6) Reliance on passive approaches; (7) Social determinants influence LBP care pathway; and (8) Health systems are ill-prepared to address LBP burden. INTERPRETATION: LBP care in LMICs did not consistently align with the best available evidence. Findings will help research prioritization in LMICs and guide global LBP clinical guidelines. FUNDING: The lead author's Fellowship was supported by the International Association for the Study of Pain.
Fish and Meat Are Often Withheld From the Diets of Infants 6 to 12 Months in Fish-Farming Households in Rural Bangladesh

Thorne-Lyman AL, Valpiani N, Akter R, Baten MA, Genschick S, Karim M, et al.

Food Nutr Bull, 2017 Sep;38(3):354-368.
PMID: 28618837 DOI: 10.1177/0379572117709417

BACKGROUND: Fish is a widely available animal-source food in Bangladesh and a rich source of nutrients, yet little is known about practices related to incorporating fish into the diets of infants and young children.
OBJECTIVE: Use dietary diversity data to explore consumption patterns of fish and high-quality food items within the household and examine factors associated with delayed introduction of fish to infants and young children.
METHODS: Cross-sectional survey of 496 households with children <36 months participating in the Aquaculture for Income and Nutrition project in Bangladesh. Data collected included household characteristics, women's dietary diversity score, and minimum dietary diversity score along with data on Infant and Young Child Feeding practices.
RESULTS: Most children (63.4%) met the threshold for minimum dietary diversity. Despite having received extensive nutrition education related to including fish in complementary foods, only half of the caretakers introduced fish at 6 months and the mean age of introduction of small fish was 8.7 months. Meat and fish were not common in infant diets but increased with child age. Concerns about bones were a major barrier to incorporating fish into infant diets.
CONCLUSION: Given its nutrient profile and widespread availability in certain contexts, fish could be an underutilized opportunity to improve nutrition and health outcomes of infants and young children. Further research, including utilizing food processing technologies, is needed to develop appropriate responses to overcome these barriers.
Field evaluation of alphacypermethrin and lambda-cyhalothrin against Aedes aegypti and Aedes albopictus in Malaysia

Sulaiman S, Karim MA, Omar B, Omar S

J Am Mosq Control Assoc, 1995 Mar;11(1):54-8.
PMID: 7616191

Alphacypermethrin (Fendona) and lambda-cyhalothrin (Icon) were evaluated against sentinel bloodfed adults and 4th-instar larvae of Aedes aegypti in a housing estate in Malaysia. The impact of both pyrethroids on field populations of Ae. aegypti and Aedes albopictus were monitored weekly using oviposition trap samples. Both alphacypermethrin and lambda-cyhalothrin showed adulticidal and larvicidal effects.
Fermentation studies of stored cocoa beans

Abdul Samah O, Ibrahim N, Alimon H, Abdul Karim MI

World J Microbiol Biotechnol, 1993 Sep;9(5):603-4.
PMID: 24420212 DOI: 10.1007/BF00386306

Acetic and lactic acid bacteria on fermented cocoa beans were maximally 2.0×10(6) and 1.9×10(6) c.f.u./g wet wt, respectively. Acetic and lactic acids were detected on the second and fourth days of fermentation and were maximally 140 and 45 mg/10 g beans, respectively. There was a positive correlation between the sizes of the relevant microbial populations and the amounts of acids produced during fermentation.
Feasibility study on the utilization of rubber latex effluent for producing bacterial biopolymers

Tang SN, Fakhru'l-Razi A, Hassan MA, Karim MI

Artif Cells Blood Substit Immobil Biotechnol, 1999 Sep-Nov;27(5-6):411-6.
PMID: 10595441

Rubber latex effluent is a polluting source that has a high biochemical oxygen demand (BOD). It is estimated that about 100 million liters of effluent are discharged daily from rubber processing factories. Utilization of this effluent such as the use of a coupled system not only can reduce the cost of treatment but also yield a fermentation feedstock for the production of bioplastic. This study initially was carried out to increase the production of organic acids by anaerobic treatment of rubber latex effluent. It was found that through anaerobic treatment the concentration of organic acids did not increase. Consequently, separation of organic acids from rubber latex effluent by anion exchange resin was examined as a preliminary study of recovering acetic and propionic acids. However, the suspended solids (SS) content in the raw effluent was rather high which partially blocked the ion-exchange columns. Lime was used to remove the SS in the rubber latex effluent. After the lime precipitation process, organic acids were found to adsorb strongly onto the anion exchange resin. Less adsorption of organic acids onto the resin was observed before the lime precipitation. This was probably due to more sites being occupied by colloidal particles on the resin thus inhibiting the adsorption of organic acids. The initial concentration of organic acids in the raw effluent was 3.9 g/L. After ion exchange, the concentration of the organic acids increased to 27 g/L, which could be utilized for production of polyhydroxyalkanoates (PHA). For PHA accumulation stage, concentrated rubber latex effluent obtained from ion exchange resins and synthetic acetic acid were used as the carbon source. Quantitative analyses from fed batch culture via HPLC showed that the accumulation of PHA in Alcaligenes eutrophus was maximum with a concentration of 1.182 g/L when cultivated on synthetic acetic acid, corresponding to a yield of 87% based on its cell dry weight. The dry cell weight increased from 0.71 to 1.67 g/L. On the other hand, using concentrated rubber latex effluent containing acetic and propionic acids resulted in reduced PHA content by dry weight (14%) but the dry cell weight increased from 0.49 to 1.30 g/L. The results clearly indicated that the cells grow well in rubber latex effluent but no PHA was accumulated. This could be due to the high concentration of propionic acid in culture broth or other factors such as heavy metals. Thus further work is required before rubber latex effluent can be utilized as a substrate for PHA production industrially.
Evaluating Bacillus flexus as bioremediators for ammonia removal in shrimp culture water and wastewater and characterizing microbial communities in shrimp pond sludge

Jasmin MY, Isa NM, Kamarudin MS, Lim KC, Karim M

Braz J Microbiol, 2024 Jan 27.
PMID: 38280093 DOI: 10.1007/s42770-024-01246-9

The accumulation of nitrogen compounds in shrimp farming water and effluent presents a major challenge. Ammonia is a form of nitrogen that limits shrimp growth due to its potential toxicity and effects on shrimp health and water quality. This study is aimed at identifying promising bioremediators from shrimp pond sludge to mitigate ammonia levels in both culture water and wastewater and at determining major bacterial communities in sludge using metagenomic analysis. A sludge sample was collected from a shrimp pond in Selangor, Malaysia, to isolate potential ammonia-removing bacteria. Out of 64 isolated strains, Bacillus flexus SS2 showed the highest growth in synthetic basal media (SBM) containing ammonium sulfate at a concentration of 70 mg/L as the sole nitrogen source. The strain was then incubated in SBM with varying pH levels and showed optimal growth at pH 6.5-7. After 24 h of incubation, B. flexus SS2 reduced the ammonia concentration from an initial concentration of 5 to 0.01 mg/L, indicating a 99.61% reduction rate, which was highest in SBM at pH 7. Moreover, the strain showed ammonia removal ability at concentrations ranging from 5 to 70 mg/L. Metagenomic analysis revealed that Proteobacteria was the most abundant phylum in the sludge, followed by Cyanobacteria, Actinobacteria, Chloraflexi, Firmicutes, and Campilobacterota. Bacillus flexus SS2 belongs to the Bacillota phylum and has the potential to serve as a bioremediator for removing ammonia from shrimp culture water and wastewater.
Enzyme production and profile by Aspergillus niger during solid substrate fermentation using palm kernel cake as substrate

Ong LG, Abd-Aziz S, Noraini S, Karim MI, Hassan MA

Appl Biochem Biotechnol, 2004 8 12;118(1-3):73-9.
PMID: 15304740

The oil palm sector is one of the major plantation industries in Malaysia. Palm kernel cake is a byproduct of extracted palm kernel oil. Mostly palm kernel cake is wasted or is mixed with other nutrients and used as animal feed, especially for ruminant animals. Recently, palm kernel cake has been identified as an important ingredient for the formulation of animal feed, and it is also exported especially to Europe, South Korea, and Japan. It can barely be consumed by nonruminant (monogastric) animals owing to the high percentages of hemicellulose and cellulose contents. Palm kernel cake must undergo suitable pretreatment in order to decrease the percentage of hemicellulose and cellulose. One of the methods employed in this study is fermentation with microorganisms, particularly fungi, to partially degrade the hemicellulose and cellulose content. This work focused on the production of enzymes by Aspergillus niger and profiling using palm kernel cake as carbon source.

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