MyMedR

Displaying publications 81 - 100 of 367 in total

Abstract:

Sort:

Antioxidants improve β-cypermethrin degradation by alleviating oxidative damage and increasing bioavailability by Bacillus cereus GW-01

Xie Y, Gong L, Liu S, Yan J, Zhao S, Xia C, et al.

Environ Res, 2023 Nov 01;236(Pt 1):116680.
PMID: 37500036 DOI: 10.1016/j.envres.2023.116680

Microbial degradation of pesticide residues has the potential to reduce their hazards to human and environmental health. However, in some cases, degradation can activate pesticides, making them more toxic to microbes. Here we report on the β-cypermethrin (β-CY) toxicity to Bacillus cereus GW-01, a recently described β-CY degrader, and effects of antioxidants on β-CY degradation. GW-01 exposed to β-CY negatively affected the growth rate. The highest maximum specific growth rate (μm) appeared at 25 mg/L β-CY. β-CY induced the oxidative stress in GW-01. The activities of superoxide dismutase (SOD), catalyse (CAT), and glutathione-S-transferase (GST) were significantly higher than that in control (p

Matched MeSH terms: Bacillus cereus/metabolism
Enhancing photosynthesis and root development for better fruit quality, aroma, and lessening of radioactive materials in key lime (Citrus aurantifolia) using Trichoderma harzianum and Bacillus thuringiensis

Salem A, Khandaker MM, Mahmud K, Alsufyani SJ, Majrashi AA, Rashid ZM, et al.

Plant Physiol Biochem, 2024 Jan;206:108295.
PMID: 38154296 DOI: 10.1016/j.plaphy.2023.108295

The present study was conducted to investigate the effects of Trichoderma harzianum and Bacillus thuringiensis alone or with gradual levels of NPK on photosynthesis, growth, fruit quality, aroma improvement and reduced radionuclides of key lime fruits. The lemon seedlings were treated with (T0) without fertilizers as control, (T1) 100g of NPK at 100%, (T2) 5 g of Trichoderma. harzianum at 50% + 50 g of NPK at 50%, (T3) 5 g of Bacillus thuringiensis at 50% + 50 g of NPK at 50 %, (T4) 7.5 g of Trichoderma harzianum at 75% + 25 g of NPK at 25 %, (T5) 7.5 g of Bacillus thuringiensis at 75% + 25 g of NPK at 25 %, (T6) 10 g of Trichoderma harzianum at 100 % and (T7)10 g of Bacillus thuringiensis at 100 %. The results showed that T2 increased net photosynthetic rate, stomatal conductance, transpiration rate, internal CO2 concentration, fresh and dry root biomass by 209%, 74%, 56%, 376%, 69.4% and 71.6%, while, T5 increased root volume, root length, and root tip number by 27.1%, 167%, and 67%, respectively over the control trees. The microbial treatments developed cortex, vascular cylinder and tracheal elements of the root. Fruit number, length, diameter, weight, pulp thickness, pulp/peel ratio, juice, total soluble solids (TSS), pigment contents and antioxidant activity increased significantly in the T2 treatment. Vitamin C, total phenols, total flavonoids, and total sugar content increased by 1.59-, 1.66-, 1.44- and 2.07- fold in T5 treated fruits compared to the control. The two microbes increased volatile compounds and decreased radionucleotides in the fruit, moreover, 27 identified and 2 (two) unmatched volatile compounds were identified by GCMS analysis. It is concluded that T. harzianum and B. thuringiensis with 25-50 g NPK treatments improved photosynthesis, root structure, fruit growth, fruit quality, aroma and lessened radionuclides in key lime fruits.

Matched MeSH terms: Bacillus thuringiensis*
Fulltext Prevalence and associated factors of delayed sputum smear conversion in patients treated for smear positive pulmonary tuberculosis: A retrospective follow up study in Sabah, Malaysia

Khor LA, A Wahid UNI, Ling LL, Liansim SMS, Oon J, Balakrishnan MN, et al.

PLoS One, 2023;18(3):e0282733.
PMID: 36877714 DOI: 10.1371/journal.pone.0282733

INTRODUCTION: Tuberculosis remains a major health problem globally and in Malaysia, particularly in the state of Sabah. Delayed sputum conversion is associated with treatment failure, drug-resistant tuberculosis and mortality. We aimed to determine the prevalence of delayed sputum conversion among smear positive pulmonary tuberculosis (PTB) patients and its associated factors in Sabah, Malaysia.
METHODS: A retrospective follow up study on all patients newly diagnosed with smear positive pulmonary tuberculosis from 2017 to 2019 was conducted at three government health clinics in Sabah, utilizing data from a national electronic tuberculosis database and medical records. Descriptive statistics and binary logistic regression were applied for data analysis. The outcome of the study was the sputum conversion status at the end of the two-month intensive treatment phase with either successful conversion to smear negative or non-conversion.
RESULTS: 374 patients were included in the analysis. Our patients were generally younger than 60 years old with no medical illness and varying proportions of tuberculosis severity as judged by radiographic appearance and sputum bacillary load upon diagnosis. Foreigners constituted 27.8% of our sample. 8.8% (confidence interval: 6.2-12.2) did not convert to smear negative at the end of the intensive phase. Binary logistic regression showed that older patients ≥60 years old (adjusted odds ratio, AOR = 4.303), foreigners (AOR = 3.184) and patients with higher sputum bacillary load at diagnosis [2+ (AOR = 5.061) and 3+ (AOR = 4.992)] were more likely to have delayed sputum smear conversion.
CONCLUSION: The prevalence of delayed sputum conversion in our study was considerably low at 8.8% with age ≥60 years old, foreigners and higher pre-treatment sputum bacillary load associated with delayed conversion. Healthcare providers should take note of these factors and ensure the patients receive proper follow up treatment.

Matched MeSH terms: Bacillus*; Lactobacillus casei*
Comparative bioassays of Bacillus thuringiensis H-14 formulations against four species of mosquitoes in Malaysia

Foo AE, Yap HH

Southeast Asian J Trop Med Public Health, 1982 Jun;13(2):206-10.
PMID: 6128794

Comparative laboratory bioassays of three formulations of Bacillus thuringiensis H-14 (IPS-78, San 402-I and Bactimos) were conducted against late 3rd/early 4th instar larvae of four species of mosquito, viz., Aedes aegypti, Culex quinquefasciatus, Anopheles balabacensis and Mansonia (Mansonioides) indiana, in Malaysia. From the average response of the mosquito larvae to the three formulations of B. thuringiensis H-14, Ae. aegypti was found to be most susceptible, followed by Cx. quinquefasciatus, An. balabacensis and M. (M.) indiana in decreasing order. The LC50 values for Ae. aegypti, Cx. quinquefasciatus, An. balabacensis and M. (M.) indiana after a 48-hour exposure to IPS-78 formulation were 50.9, 129.3, 117.8 and 169.6 International Toxic Unit (ITU) Ae. ae./l; to San 402-I formulation were 54.6, 223.1, 405.1 and 177.6 ITU Ae. ae/l and to Bactimos formulation were 57.2, 175.7, 35.6 and 514.5 ITU Ae. ae./l respectively. The efficacy of the bacterial product was also found to be determined by its formulation in relation to the feeding and resting habits of the mosquito larvae. No delayed pupation or emergence was observed on the larvae exposed to B. thuringiensis H-14 at sub-lethal concentrations.

Matched MeSH terms: Bacillus thuringiensis*
Efficacy of a Bacillus thuringiensis israelensis tablet formulation, vectobac DT, for control of dengue mosquito vectors in potable water containers

Benjamin S, Rath A, Fook CY, Lim LH

Southeast Asian J Trop Med Public Health, 2005 Jul;36(4):879-92.
PMID: 16295540

VectoBac DT, a tablet formulation of Bacillus thuringiensis israelensis (Bti) was evaluated for the potential control of dengue vectors in various types of potable water containers. On introduction to containers, the tablet sinks to the bottom and the Bti toxins are found concentrated at the sides and the base, while the treated water column is free of Bti toxins within 24 hours after tablet introduction. In a simulated study, earthen, HDPE and plastic containers were kept covered and laboratory-bred larvae were introduced to determine the control by the tablet. The efficacy and persistence of the tablet, with a control of > 90%, was significantly longer in earthen containers in comparison to the HDPE and plastic containers. Efficacy and persistence were observed in earthen containers for a minimum period of 5.5 months (166 days) both without water replenishment and with weekly, 50% water volume, replenishment, and for a maximum period of 2.2 months (66 days) with daily, 50% water volume, replenishment. In plastic and HDPE containers, the tablet activity had a persistence of 2.1 months (63 days) without water replenishment and 1.8 months (54 days) with weekly water replenishment. The efficacy and persistence of the VectoBac DT was significantly longer in the earthen containers, with or without regularly treated water exchange, due to the Bti toxins being embedded in the porous earthen container surfaces, which protects them from rapid degradation. Lesser toxin amounts are removed from the water column during water exchange. The efficacy of VectoBac DT was also evaluated for the control of natural infestation of Aedes larvae which were resistant to temephos at the WHO diagnostic dosage of 0.012 mg/l. The tablet significantly reduced the pupal density by 8 fold in earthen containers for 67 days and 5 fold in HDPE containers for 55 days in comparison to untreated containers (p < 0.05). However, the tablet was effective for a shorter period of 25 days post-tablet-introduction due to fungal infestation in the treated plastic containers. There is a need to determine the capacity of the VectoBac DT to reduce the dengue vector population to a threshold which will prevent dengue outbreaks in dengue endemic areas.

Matched MeSH terms: Bacillus thuringiensis*
Fulltext Pulp Enhancement of Oil Palm Empty Fruit Bunches (OPEFBs) via Biobleaching by Using Xylano-Pectinolytic Enzymes of Bacillus amyloliquefaciens ADI2

Nawawi MH, Mohamad R, Tahir PM, Asa'ari AZ, Saad WZ

Molecules, 2021 Jul 14;26(14).
PMID: 34299554 DOI: 10.3390/molecules26144279

The present work reports the biobleaching effect on OPEFB pulp upon utilisation of extracellular xylano-pectinolytic enzymes simultaneously yielded from Bacillus amyloliquefaciens ADI2. The impacts of different doses, retention times, pH, and temperatures required for the pulp biobleaching process were delineated accordingly. Here, the OPEFB pulp was subjected to pre-treatment with xylano-pectinolytic enzymes generated from the same alkalo-thermotolerant isolate that yielded those of higher quality. Remarkable enhanced outcomes were observed across varying pulp attributes: for example, enzyme-treated pulp treated to chemical bleaching sequence generated improved brightness of 11.25%. This resulted in 11.25% of less chlorine or chemical consumption required for obtaining pulp with optical attributes identical to those generated via typical chemical bleaching processes. Ultimately, the reduced consumption of chlorine would minimise the organochlorine compounds found in an effluent, resulting in a lowered environmental effect of paper-making processes overall as a consequence. This will undoubtedly facilitate such environmentally-friendly technology incorporation in the paper pulp industry of today.

Matched MeSH terms: Bacillus amyloliquefaciens/metabolism*
Bacillus cereus: A review of "fried rice syndrome" causative agents

Leong SS, Korel F, King JH

Microb Pathog, 2023 Dec;185:106418.
PMID: 37866551 DOI: 10.1016/j.micpath.2023.106418

"Fried rice syndrome" originated from the first exposure to a fried rice dish contaminated with Bacillus cereus. This review compiles available data on the prevalence of B. cereus outbreak cases that occurred between 1984 and 2019. The outcome of B. cereus illness varies dramatically depending on the pathogenic strain encounter and the host's immune system. B. cereus causes a self-limiting, diarrheal illness caused by heat-resistant enterotoxin proteins, and an emetic illness caused by the deadly toxin named cereulide. The toxins together with their extrinsic factors are discussed. The possibility of more contamination of B. cereus in protein-rich food has also been shown. Therefore, the aim of this review is to summarize the available data, focusing mainly on B. cereus physiology as the causative agent for "fried rice syndrome." This review emphasizes the prevalence of B. cereus in starchy food contamination and outbreak cases reported, the virulence of both enterotoxins and emetic toxins produced, and the possibility of contaminated in protein-rich food. The impact of emetic or enterotoxin-producing B. cereus on public health cannot be neglected. Thus, it is essential to constantly monitor for B. cereus contamination during food handling and hygiene practices for food product preparation.

Matched MeSH terms: Bacillus cereus/metabolism
Fulltext 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 Mar;55(1):529-536.
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.

Matched MeSH terms: Bacillus*
Relevance of diffusion through bacterial spore coats/membranes and the associated concentration boundary layers in the initial lag phase of inactivation: a case study for Bacillus subtilis with ozone and monochloramine

Fernando WJ, Othman R

Math Biosci, 2006 Feb;199(2):175-87.
PMID: 16387333

Disinfectants are generally used to inactivate microorganisms in solutions. The process of inactivation involves the disinfectant in the liquid diffusing towards the bacteria sites and thereafter reacting with bacteria at rates determined by the respective reaction rates. Such processes have demonstrated an initial lag phase followed by an active depletion phase of bacteria. This paper attempts to study the importance of the combined effects of diffusion of the disinfectant through the outer membrane of the bacteria and transport through the associated concentration boundary layers (CBLs) during the initial lag phase. Mathematical equations are developed correlating the initial concentration of the disinfectant with time required for reaching a critical concentration (C*) at the inner side of the membrane of the cell based on diffusion of disinfectant through the outer membranes of the bacteria and the formation of concentration boundary layers on both sides of the membranes. Experimental data of the lag phases of inactivation already available in the literature for inactivation of Bacillus subtilis spores with ozone and monochloramine are tested with the equations. The results seem to be in good agreement with the theoretical equations indicating the importance of diffusion process across the outer cell membranes and the resulting CBL's during the lag phase of disinfection.

Matched MeSH terms: Bacillus subtilis/drug effects*; Bacillus subtilis/metabolism*; Bacillus subtilis/physiology
Fulltext Genomic data of two Bacillus and two Pseudomonas strains isolated from the acid mine drainage site at Mamut Copper Mine, Ranau, Malaysia

Low YY, Chin GJWL, Joseph CG, Musta B, Rodrigues KF

Data Brief, 2020 Dec;33:106486.
PMID: 33225029 DOI: 10.1016/j.dib.2020.106486

The genomic data of four bacteria strains isolated from the abandoned Mamut Copper Mine, an Acid Mine Drainage (AMD) site is presented in this report. Two of these strains belong to the genus Bacillus, while the other two belong to the genus Pseudomonas. The draft genome size of Pseudomonas sp. strain MCMY3 was 6,396,595 bp (GC: 63.3%), Bacillus sp. strain MCMY6 was 6,815,573 bp (GC: 35.2%), Bacillus sp. strain MCMY13 was 5,559,059 bp (GC: 35.5%) and Pseudomonas sp. strain MCMY15 was 7,381,777 bp (GC: 64.8%). These four genomes contained 493, 495, 495 and 579 annotated subsystems, respectively. The sequence data are available at GenBank sequence read archive with accessions numbers SRX7859406, SRX7859404, SRX7859405 and SRX7293032 for strains MCMY3, MCMY6, MCMY13 and MCMY15, respectively.

Matched MeSH terms: Bacillus
Fulltext Molecular characterization of culturable bacteria in raw and commercial Edible Bird Nests (EBNs)

Wong, S.F., Lim, P.K.C., Mak, J.W., Ooi, S.S., Chen, D.K.F.

International Food Research Journal, 2018;25(3):966-974.
MyJurnal

Edible bird nests (EBNs) are highly demanded globally. The industry was recently affected by an import ban to China due to high nitrite levels.Subsequently, many concerns have been raised. In this study, the microbial composition of both raw and commercial EBNs was investigated. The raw EBNs were purchased from swiftlet farms: Kuala Sanglang (Perlis), Pantai Remis (Perak), Kluang (Johor), Kajang (Selangor) and Kota Bharu (Kelantan). The commercial nests were purchased from five different Chinese traditional medicinal shops (Companies A-E) in Malaysia and one from Indonesia (Medan). A total of 123 and 34 isolates were successfully identified from unboiled raw and commercial EBNs respectively. The highest average CFU (1.77 x 104) was associated with raw EBNs obtained from Kluang, while for the commercial EBNs, those obtained from Company M1 had the highest CFU (5.50 x 104). Bacillus sp. accounted for the highest isolated species from both unboiled raw and commercial EBNs. Bacillus sp. and Brevibacillus sp. were mainly isolated from the boiled EBNs. Bacillus spp. were the dominant bacterial groups in all the raw EBNs except for those obtained from Kajang. The average number of bacteria isolated from the raw EBNs (average = 7) was higher compared with those isolated from the commercial EBNs (average = 4). The highest average number of bacterial isolates was reported in the raw EBNs obtained from Kota Bharu. Among the commercial EBNs, one EBN sample each from Companies A and M1 showed the highest number of isolates (n = 10). In general, there was a significant reduction in the number of bacteria isolated after boiling the EBNs. Raw EBNs obtained from Kajang had a distinct pool of bacterial species where the majority of the isolated species belonged to Staphylococcus species. The associated health impacts of these microorganisms to the consumers and public need to be addressed.

Matched MeSH terms: Bacillus; Brevibacillus
Fulltext Draft Genome Sequence of the Prazosin-Degrading Bacillus sp. Strain PR5, Isolated from a River Receiving Hospital and Urban Wastewater in Malaysia

Ahmad Sabri NS, Mohd Mohsi NF, Apandi A, Yusof N, Megat Mohd Noor MJ, Md Akhir FN, et al.

Microbiol Resour Announc, 2021 Mar 18;10(11).
PMID: 33737348 DOI: 10.1128/MRA.00025-21

We report the complete genome sequence of Bacillus sp. strain PR5, isolated from a river receiving hospital and urban wastewater in Malaysia, which demonstrated a high capability for degrading prazosin. This genome sequence of 4,525,264 bp exhibited 41.5% GC content, 4,402 coding sequences, and 32 RNAs.

Matched MeSH terms: Bacillus
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.

Matched MeSH terms: Bacillus
Fulltext Bacillus cereus and Bacillus thuringiensis in ready-to-eat cooked rice in Malaysia

Sandra, A., Afsah-Hejri, L., Tunung, R., Tuan Zainazor, T. C., Tang, J. Y. H., Ghazali, F. M., et al.

International Food Research Journal, 2012;19(3):829-836.
MyJurnal

Bacillus cereus (B. cereus) isolates are toxigenic and can cause food poisoning. Cooked rice is
a potentially hazardous food, especially in tropical countries. The aim of this study was to determine the prevalence of B. cereus and B. thuringiensis in raw and cooked rice marketed in Selangor, Malaysia. In this research combination of Most Probable Number - Polymerase Chain Reaction (MPN-PCR) was used to detect gyrB gene in B. cereus and B. thuringiensis. Five local varieties of raw rice samples were negative for B. thuringiensis but all (100%) were positive for B. cereus. A total of 115 cooked rice samples (nasi lemak, nasi briyani, nasi ayam and nasi putih) were studied for the presence of B. cereus and B. thuringiensis. Nasi ayam was found to have the highest prevalence (100%) of B. cereus compared to nasi putih (76.2%) and nasi lemak (70.4%). Nasi briyani had the lowest prevalence (50%) of B. cereus. The frequencies of B. thuringiensis were found to be 10, 30 and 35.2 % in nasi putih and nasi ayam, nasi briyani and nasi lemak, respectively. The range of B. cereus and B. thuringiensis in the samples was from < 3 to 1100 MPN/g in different samples. Maximum number of B. cereus was observed in nasi lemak, nasi briyani and nasi putih ( > 1100 MPN/g) while nasi ayam showed less contamination (460 MPN/g) with B. cereus which was significantly different (P < 0.05 ) from others. The number of B. thuringiensis in nasi lemak, nasi briyani, nasi putih and nasi ayam were found to be >1100, 93, 9.2 and 3.6 MPN/g, respectively.

Matched MeSH terms: Bacillus cereus
Draft Genome Sequence of a Biosurfactant-Producing Bacillus subtilis UMX-103 Isolated from Hydrocarbon-Contaminated Soil in Terengganu, Malaysia

Abdelhafiz YA, Manaharan T, BinMohamad S, Merican AF

Curr Microbiol, 2017 Apr 17.
PMID: 28417189 DOI: 10.1007/s00284-017-1249-3

The draft genome here presents the sequence of Bacillus subtilis UMX-103. The bacterial strain was isolated from hydrocarbon-contaminated soil from Terengganu, Malaysia. The whole genome of the bacterium was sequenced using Illumina HiSeq 2000 sequencing platform. The genome was assembled using de novo approach. The genome size of UMX-103 is 4,234,627 bp with 4399 genes comprising 4301 protein-coding genes and 98 RNA genes. The analysis of assembled genes revealed the presence of 25 genes involved in biosurfactant production, where 14 of the genes are related to biosynthesis and 11 of the genes are in the regulation of biosurfactant productions. This draft genome will provide insights into the genetic bases of its biosurfactant-producing capabilities.

Matched MeSH terms: Bacillus subtilis
Fulltext Prospecting Agro-waste Cocktail: Supplementation for Cellulase Production by a Newly Isolated Thermophilic B. licheniformis 2D55

Kazeem MO, Shah UKM, Baharuddin AS, AbdulRahman NA

Appl Biochem Biotechnol, 2017 Aug;182(4):1318-1340.
PMID: 28176140 DOI: 10.1007/s12010-017-2401-z

Bacteria isolated from thermophilic environment that can produce cellulase as well as utilise agro-waste biomass have a high potential for developing thermostable cellulase required in the biofuel industry. The cost for cellulase represents a significant challenge in converting lignocellulose to fermentable sugars for biofuel production. Among three potential bacteria examined, Bacillus licheniformis 2D55 (accession no. KT799651) was found to produce the highest cellulolytic activity (CMCase 0.33 U/mL and FPase 0.09 U/mL) at 18-24 h fermentation when grown on microcrystalline cellulose (MCC) as a carbon source in shake flask at 50 °C. Cellulase production process was further conducted on the untreated and NaOH pretreated rice straw (RS), rice husk (RH), sugarcane bagasse (BAG) and empty fruit bunch (EFB). Untreated BAG produced the highest FPase (0.160 U/mL), while the highest CMCase (0.150 U/mL) was supported on the pretreated RH. The mixture of untreated BAG and pretreated RH as agro-waste cocktail has remarkably improved CMCase (3.7- and 1.4-fold) and FPase (2.5- and 11.5-fold) compared to the untreated BAG and pretreated RH, respectively. The mechanism of cellulase production explored through SEM analysis and the location of cellulase enzymes of the isolate was also presented. Agro-waste cocktail supplementation provides an alternative method for an efficient production of cellulase.

Matched MeSH terms: Bacillus licheniformis/genetics; Bacillus licheniformis/isolation & purification; Bacillus licheniformis/metabolism*
Toxicity assessment of reduced graphene oxide and titanium dioxide nanomaterials on gram-positive and gram-negative bacteria under normal laboratory lighting condition

Ahmad NS, Abdullah N, Yasin FM

Toxicol Rep, 2020;7:693-699.
PMID: 32528857 DOI: 10.1016/j.toxrep.2020.04.015

Toxicity effect of reduced graphene oxide (rGO) and titanium dioxide (TiO2) nanomaterials (NMs) on Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacteria was assessed. For both strains, study demonstrated that the toxicity was time and concentration dependent which led to reduction in growth rate and cell death. Upon NMs exposure, an instantaneous cell death in E. coli culture was observed. This is in contrast with B. subtilis, in which the culture growth remained in the log phase; however their growth rate constant,

μ
g

was reduced by ∼70%. The discrepancy between E. coli and B. subtilis was due to strain-specific response upon contact with NMs. TEM, SEM and EDX analysis revealed direct physical surface-surface interaction, as evidence from the adherence of NMs on the cell surface.

Matched MeSH terms: Bacillus subtilis
Green biorefinery: Microalgae-bacteria microbiome on tolerance investigations in plants

Bui-Xuan D, Tang DYY, Chew KW, Nguyen TDP, Le Ho H, Tran TNT, et al.

J Biotechnol, 2022 Jan 10;343:120-127.
PMID: 34896159 DOI: 10.1016/j.jbiotec.2021.12.002

Co-culture of microalgae and microorganisms, supported with the resulting synergistic effects, can be used for wastewater treatment, biomass production, agricultural applications and etc. Therefore, this study aimed to explore the role of Bacillus subtilis (B. subtilis) in tolerance against the harsh environment of seafood wastewater, at which these microalgal-bacterial flocs were formed by microalgae cultivation. In this present study, B. subtilis isolated from the cultivation medium of Chlorella vulgaris and exposed to different salinity (0.1-4% w/v sodium chloride) and various pH range to determine the tolerant ability and biofilm formation. Interestingly, this bacteria strain that isolated from microalgae cultivation medium showed the intense viability in the salt concentration exceeding up to 4% (w/v) NaCl but demonstrated the decrease in cell division as environmental culture undergoing over pH 10. Cell viability was recorded higher than 71% and 92% for B. subtilis inoculum in media with salt concentration greater than 20 gL-1 and external pH 6.5-9, respectively. This showed that B. subtilis isolated from microalgal-bacteria cocultivation exhibited its tolerant ability to survive in the extremely harsh conditions and thus, mitigating the stresses due to salinity and pH.

Matched MeSH terms: Bacillus subtilis
Fulltext Antifungal Prospect of Bacillus cereus Postbiotic on Crustacean Pathogen, Lagenidium thermophilum

Elliecpearl Jasca J, Annita Seok KY, Suraini L, Chun YA, Julian R, Sano M, et al.

Biocontrol Sci, 2021;26(4):201-205.
PMID: 35013016 DOI: 10.4265/bio.26.201

Pathogenic marine fungi, Lagenidium thermophilum is known causative agent in the crustacean industry. Current disinfection practice in hatchery has risks and negative impacts which prompts suitable substitute to synthetic antifungal agents. Thus, this study was conducted to evaluate the antifungal potential of postbiotic from four potential probiotics towards marine oomycetes, L. thermophilum IPMB 1401. The screening test showed that the Lactobacillus plantarum GS12 and Bacillus cereus GS15 postbiotics were positive for antifungal activity on L. thermophilum IPMB 1401. These two bacterial extracts have minimum inhibitory concentration （MIC） at 50%. The toxicity assay on MIC level of the postbiotic revealed that the cumulative mortality of brine shrimp nauplii exposed to B. cereus postbiotic was significantly lower compared to L. plantarum GS12 postbiotic and formalin. This indicates a high potential of B. cereus GS15 as a prospect for alternative control method for fungal infections in the crustacean culture industry.

Matched MeSH terms: Bacillus cereus
A novel organic solvent tolerant lipase from Bacillus sphaericus 205y: extracellular expression of a novel OST-lipase gene

Sulong MR, Abdul Rahman RN, Salleh AB, Basri M

Protein Expr Purif, 2006 Oct;49(2):190-5.
PMID: 16769222

An organic solvent tolerant (OST) lipase gene from Bacillus sphaericus 205y was successfully expressed extracellularly. The expressed lipase was purified using two steps purification; ultrafiltration and hydrophobic interaction chromatography (HIC) to 8-fold purity and 32% recovery. The purified 205y lipase revealed homogeneity on denaturing gel electrophoresis and the molecular mass was at approximately 30 kDa. The optimum pH for the purified 205y lipase was 7.0-8.0 and its stability showed a broad range of pH value between pH 5.0 to 13.0 at 37 degrees C. The purified 205y lipase exhibited an optimum temperature of 55 degrees C. The activity of the purified lipase was stimulated in the presence of Ca2+ and Mg2+. Ethylenediaminetetraacetic acid (EDTA) has no effect on its activity; however inhibition was observed with phenylmethane sulfonoyl fluoride (PMSF) a serine hydrolase inhibitor. Organic solvents such as dimethylsulfoxide (DMSO), methanol, p-xylene and n-decane enhanced the activity. Studies on the effect of oil showed that the lipase was most active in the presence of tricaprin (C10). The lipase exhibited 1,3 positional specificity.

Matched MeSH terms: Bacillus/enzymology*; Bacillus/genetics; Bacillus/chemistry

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links