Muskhazli Mustafa

Bacillus cereus as a biotemplating agent for the synthesis of zinc oxide with raspberry- and plate-like structures

Currently the development of green chemistry approach with the use of biomaterial-based activities of microbial cells in the synthesis of various nanostructures has attracted a great attention. In this study, we report on the use of bacterium, Bacillus cereus as a biotemplating agent for the formation of zinc oxide nanoparticles with raspberry- and plate-like structures through a simple thermal decomposition of zinc acetate by maintaining the original pH of the reaction mixtures. Possible mechanism on the formation of the nanostructures is proposed based on the surface chemistry and biochemistry processes involved organic-inorganic interactions between zinc oxide and the microbial cells.

Evaluation on physical, chemical and biological properties of casts of geophagous earthworm, Metaphire tschiliensis tschiliensis

Earthworms are soil dwellers that have profound effects on soil ecosystem. Their feeding and burrowing activities help to incorporate soil particles with organic matter and redistribute them back into the soil via casts. The casts produced enhance microbial activities in soil that promote nutrient cycling. The present study was carried out to examine the physical, chemical and biological properties of casts produced by soil dwelling earthworm, Metaphire tschiliensis tschiliensis. Prior to inoculation of earthworms, the soil was incubated for two weeks at room temperature with moisture content of 20%. Worm worked soil and earthworm casts produced were collected for analysis after one month. Our results demonstrated that earthworm casts contained higher organic matter (9.84 ± 0.60%) and humic acid (1.33 ± 0.25%) compared to bulk soil. Total N, Ca, S, Al and Zn contents were also found to be higher in earthworm casts. Besides that, earthworm casts exhibited higher colony forming units (CFU), indicating the presence of higher microbial population. The study suggested that cast produced by M. tschiliensis tschiliensis could improve the physical and chemical properties of the soil. It also contained higher microbial population compared to soil without earthworm.

Rapid biodegradation of polycyclic aromatic hydrocarbons (PAHs) using effective Cronobacter sakazakii MM045 (KT933253)

Graphical abstract

Klebsiella sp. FIRD 2, a TBT-resistant bacterium isolated from contaminated surface sediment along Strait of Johor Malaysia.

A possible tributyltin (TBT)-degrading bacterium isolated from contaminated surface sediment was successfully identified as Klebsiella sp. FIRD 2. It was found to be the best isolate capable of resisting TBT at a concentration of 1000 μg L(-1). This was a concentration above the reported contaminated level at the sampling station, 790 μg L(-1). Further studies revealed that the isolate was Gram negative and resisted TBT concentrations of up to 1500 μg L(-1) in a Minimal Salt Broth without the addition of any carbon source within the first 48 h of incubation. It is expected that additional work could be conducted to check the degradation activity of this new isolate and possibly improve the degradation capacity in order to contribute to finding a safe and sustainable remediation solution of TBT contamination.

The Occurrence of Blood Disease of Banana in Selangor, Malaysia

Bacterial wilt disease has caused a serious threat to the banana industry in Malaysia. The disease is always associated with Moko disease caused by Ralstonia solanacearum. The bacterium forms irregular round, creamy colonies with red centres when cultured on Kelman’s tetrazolium chloride (TZC) medium. Moko disease has been interchangeably identified as blood disease as both of them cause similar wilting symptoms on banana. Therefore, the present study was carried out to detect the occurrence of bacterial wilt in Selangor through comprehensive procedures on morphology, molecular, pathogenicity and specificity tests. Isolation of bacteria was conducted on infected plant samples (fruit stalk, fruit pulps, stem and root) collected in the field by plating on TZC medium. Bacteria colonies that are Gram-negative, oxidase-positive, and obligate aerobe were chosen for further identification through polymerase chain reaction (PCR) using 759F and 760R primers. Molecular identification showed the bacteria that colonized the infected plants is confirmed as BDB, which is very closely related to R. solanacearum. After Koch’s Postulate and pathogenicity test on tomato, wilting symptoms were found on all banana plantlets after two weeks. The bacterium did not cause any wilting symptom on tomato plantlets. The present study revealed the distribution of blood disease in Selangor, after the first report in Perak. It also suggested that both morphology and DNA-based identification are necessary for the detection of the pathogen that causes bacterial wilt in banana.

Isolation, characterization, and identification of potential Diuron-degrading bacteria from surface sediments of Port Klang, Malaysia

Diuron is an alternative biocide suggested to replace organotin in formulating antifouling paints to be applied on water-going vessels hull. However, it is potentially harmful to various non-targeted marine organisms due to its toxic properties. Present study aimed to isolate, screen and identify the potential of Diuron-degrading bacteria collected from the marine sediments of Port Klang, Malaysia. Preliminary screening was conducted by exposing isolated bacteria to 430ng/L (background level), followed by 600ng/L and 1000ng/L of Diuron concentrations. Nine bacteria colonies survived the exposure of the above concentrations. However, only two strains can tolerate to survive up to 1000μg/L, which were then characterised and identified using phenotypic tests and the standard 16S rRNA molecular identification. The strains were identified as Comamonas jiangduensis SZZ 10 and Bacillus aerius SZZ 19 (GenBank accession numbers: KU942479 and KU942480, respectively). Both strains have the potential of Diuron biodegradation for future use.

Potential role of endogeic earthworm Pontoscolex corethrurus in remediating banana blood disease: a preliminary observation

Blood disease is a destructive bacterial infection that causes severe yield loss to the banana industry. Ideally, an environmental friendly yet practical approach is necessitated in the search for effective treatment against the disease. Endogeic earthworms are soil biota that help in improving soil physico-chemical and biological properties and thuspromote plant health. The present study assessed the effect of Pontoscolex corethrurus on banana infected by blood disease. The effect of earthworms was evaluated through observations on stem and root morphology, anatomy and total phenolic contents (TPC). P. corethrurus was inoculated into polybags planted with banana plantlets; inoculation of blood disease bacterium (BDB) into the roots of the plantlets was done using a drenching method. Stem and root sections of the plantlets were preserved in FAA for histological study upon harvest. The remaining sections were freeze-dried for TPC analysis. Root sections of plantlets infected with BDB showed lower root biomass compared to the control and earthworm-inoculated plantlets. Observations under microscope also showed that tissue necrosis at the vascular bundles of infected roots were more severe compared to the earthworm-inoculated and unaffected plantlets. Plantlets inoculated with earthworms had the highest root TPC, followed by the unaffected plantlets and plantlets infected with BDB. Although infected plantlets with earthworm inoculation showed disease symptoms, the disease severity was slightly less. The results suggested the potential role of P. corethrurus in improving plant health for disease management and sustainable agriculture.

Potential of neem leaf-empty fruit bunch-based vermicompost as biofertiliser-cum-biopesticide: Chemical properties, humic acid content and enzymes (protease and phosphatase) activity in vermicompost (Part I)

The palm oil industry generates empty fruit bunch (EFB) in large quantities, which need to be optimally exploited to obtain maximum benefits from their uses. Vermicomposting of EFB with neem leaves is of great interest, as the end product might function as biofertiliser as well as biopesticide. Therefore, vermicomposting of different ratios of EFB and neem leaves using Eudrilus eugeniae as a composting agent was conducted. The results showed that the vermicompost produced was lower in pH, total organic carbon and the C/N ratio, but higher in humic acid content compared to the earthworm free control. The addition of neem leaves as a mixture of EFB-based vermicompost contributed to the enrichment in some important plant nutrients, such as total and available N, P, K and Ca. Results suggested that the addition of 10% neem leaves would enhance the earthworm biomass as well as nutrient contents, protease and phosphatase activity in vermicompost.