1.Screening of ligninase-producing bacteria from south east Pahang peat swamp forest soil
Muhamad Aidilfitri Mohamad Roslan, Zaima Azira Zainal Abidin, Suhaila Mohd Omar
Malaysian Journal of Microbiology 2016;12(6):433-437
Aims: Research on lignin degradation capability is previously restricted exclusively to fungal enzymes. However, recent
studies had successfully revealed several soil bacterial strains that were able to produce ligninolytic enzymes. These
bacterial ligninolytic enzymes were claimed to be more specific in catalysing cleavage of certain linkages between
phenolic units of lignin polymers as compared to fungal enzymes. The present study focuses on screening for ligninaseproducing
bacteria isolated from South East Pahang Peat Swamp Forest (SEPPSF) soil using agar-based assay.
Methodology and results: Thirteen isolates used in this study, which were selected based on distinctive colony
morphology from our previous isolation work, showed decolourisation zone on Azure B plates screening. The ratio of
decolourisation zones were measured to the ratio of the colony size and the biggest ratio was 2.22 by isolate AR1. Only
4 out of the 13 isolates were able to grow on lignin plates. Subsequently, the 4 isolates, AR3, AR8, AR10 and AR13
were tested on M1 agar supplemented with 3 ligninolytic enzyme indicator compounds which were tannic acid (TA),
guaiacol and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) respectively. All four isolates showed
growth on TA plates while only AR10 showed a clear brown coloration. An Intense reddish-brown colour formation was
observed around the colony of isolates AR3 and AR10 on guaiacol plates while none exhibited green coloration around
the colonies when tested on ABTS plates.
Conclusions, significance and impacts of study: Isolate AR10 that was identified as Serratia sp. was perceived to be
a potential ligninase-producer, though in-depth analysis has to be conducted in the future to determine the specific
ligninolytic enzyme activities and characteristics. The application of different substrates is essential to investigate the
ligninolytic potential and reaction of those bacterial enzymes towards different indicator compounds. This study is a
preliminary endeavour concerning potential ligninolytic enzymes from bacteria as biocatalysts in various industrial
processes. This is the first report on preliminary study for ligninolytic activities of soil bacteria from SEPPSF soil.
2.Comparison of various culture media effectiveness in the isolation of bacteria from Pekan peat swamp forest soil
Noor Nazihah Ghazali, Mohamad Mukhlis Mohamad Khairul Adilah ; Zaima Azira Zainal Abidin ; Suhaila Mohd. Omar
Malaysian Journal of Microbiology 2016;12(6):450-454
Aims: Previously described as non-favorable-microbial habitat, peat swamp forest has its own features, which are
extremely acidic, poor in nutrient, water-logged and anoxic environment where rate of decomposition of plant litters is
quiet slow. Interestingly, current research has proven that there is diversity of microbial communities in this ecosystem.
The main objective of this study is to isolate bacteria from Pekan peat swamp forest soil that play a role in the
decomposition of plant litters through cultivation on different agar-based medium. The success of isolation of bacteria
from this neglected habitat could open the opportunity in unleashing the specific role of bacteria in peat swamp plant
litter degradation as well as potential biotechnological application of these bacteria in lignocellulose-related industry.
Methodology and results: To mimic the peat condition that is low in nutrient and comprised of plant debris, M1 and
peat agar supplemented with cellulose, glucose, lignin and xylan were used. Specifically, for the isolation of
actinomycetes, dry and wet heat pre-treatments were applied to the soil samples. Then, the samples were cultivated on
three different agars which were oatmeal agar as well as M1 and peat agar supplemented with glucose. Enrichment
method was applied in the isolation of cellulase-producing bacteria. It was found that higher number of bacteria and
actinomycetes were successfully isolated from peat agar, followed by oatmeal agar and M1. In fact, more actinomycetes
were isolated from soil that was treated with wet heat pre-treatment compared to dry heat pre-treatment and on peat
agar compared to M1 and oatmeal agar. This finding is promising, indicating that the application of peat water in the
agar-based medium is useful to mimic the actual environment of peat swamp and increase the possibility to isolate
indigenous bacteria. Primary screening of isolates from samples enriched with carboxymethyl cellulose (CMC) showed
positive result of decolourisation zone on Azo-CM-Cellulose agar indicating the ability of isolates to degrade cellulose
compound.
Conclusions, significance and impacts of study: The study indicates the effectiveness of different culture media in
successful isolation of bacteria including actinomycetes. Using the enrichment method, bacteria that are able to degrade
cellulose compound was successfully isolated even though it is well known that plant litter degradation in the peat
swamp environment happens at very slow rates.
Bacteria
3.A sudden paediatric death due to hand, foot and mouth disease:the importance of vigilance
Razuin Rahimi ; Effat Omar ; Tuan Suhaila Tuan Soh ; Siti Farah Alwani Mohd Nawi ; Shahidan Md Noor
The Malaysian Journal of Pathology 2017;39(2):167-170
Background: Hand, foot and mouth disease (HFMD) is caused by enteroviruses such as Coxsackie
virus A16 (CVA16) and Enterovirus 71 (EV71). The diagnostic hallmarks are oral ulcers and
maculo-papular or vesicular rash on the hands and feet. Severe form of this disease can lead to
death due to neurological and cardiopulmonary complications. This case report aims to describe a
fatal case of HFMD with minimal oral and skin manifestations. Case report: A four-year-old girl
was brought to a hospital after suddenly becoming unresponsive at home. She had a history of
fever and lethargy for three days prior to her demise. The patient, and five other children in her
neighbourhood had been diagnosed to have HFMD at a local health clinic; the other children had
recovered without complications. Results: Autopsy revealed a few punctate, sub-epidermal vesicles
measuring 1 to 2 mm on the palm of her right hand and sole of the right foot, visible only with a
magnifying glass. Internal examination revealed prominent nodularity at the oro- and hypopharynxes.
The lungs were markedly congested and oedematous. Histopathology of the lung showed marked
oedema and haemorrhage with mild pneumonic changes. Oedema with increase in macroglia
and astrocytic proliferation were seen in the cerebral tissue, but no lymphocytic infiltration was
evident. Enterovirus EV71 was detected by polymerase chain reaction in samples from the lung,
cerebrospinal fluid and serum. The cause of death was given as HFMD complicated by pneumonia.
Conclusion: Fatal HFMD may have minimal signs. A complete history, careful physical examination
and relevant investigations lead to a diagnosis at post mortem examination. Awareness of the subtle
signs and rapid deterioration associated with a fatal case of HFMD is a challenge to clinicians who
encounter these cases.