1.Characteristics of limestone soil collected from Gunung Lang, Perak and metagenomic analysis of the soil microbial community
Yen Teng Tai ; Nazalan Najimudin ; Kumar Sudesh
Malaysian Journal of Microbiology 2015;11(4):373-382
Aims: This project was aimed to study the microbial diversity of the limestone soil and its correlation with the
environment.
Methodology and results: The study was carried out using samples obtained from Gunung Lang, Ipoh, Perak in
August 2013. X-ray diffraction analysis of the rock structure confirmed that the samples were of limestone origin.
Besides that, soil analysis revealed that this area was fertile and rich in nutrients. It therefore served as a suitable habitat
for microorganismal diversity to flourish. This was proven by the 16S rDNA metagenomic analysis which targeted on
16S rDNA variable region V3-V5 using Illumina MiSeq sequencer. Using this approach, a variety of microorganisms was
identified and many yet to be characterized microorganisms were detected from this area.
Conclusion, significance and impact of study: This is the first study in Malaysia that aimed to study the microbial
diversity of limestone soils through metagenomic approach. The study showed that limestone is rich in microbial
diversity and it is a place worth looking for novel microbes and genes of interest in biotechnology.
Calcium Carbonate
2.Isolation and identification of bacteria and fungi growing spontaneously on polyhydroxyalkanoate pellets recovered by a new biological process
Somarajan Pyary ; Kumar Sudesh ; Hideyuki Nagao
Malaysian Journal of Microbiology 2016;12(3):221-227
Aims: The study was carried out to isolate and identify the spontaneously growing populations of bacteria and fungi on
the surface of biologically recovered polyhydroxyalkanoate (PHA) copolymer, poly(3-hydroxybutyrate-co-3-
hydroxyhexanoate) [P(3HB-co-3HHx)].
Methodology and results: Large-scale PHA biosynthesis was carried out using 300 L fermenter and a biological
methodology developed in our laboratory was utilized for PHA recovery. Using standard microbiological and molecular
biology techniques the naturally growing microbial populations on the surface of biologically recovered PHA were
identified. Scanning electron microscopy (SEM) analysis showed that the identified bacterial (Bacillus cereus and
Burkholderia cepacia) and fungal isolates (Aspergillus niger, Byssochlamys nivea, Penicillium citrinum and Penicillium
griseofulvum) were able to grow on and degrade the P(3HB-co-3HHx) copolymer.
Conclusion, significance and impact of study: This is the first report on biologically recovered PHA pellet addressing
the occurrence of microorganisms that grew spontaneously on it during storage under laboratory conditions. Fungi
appeared to be dominant over bacteria in their ability to colonize the biologically recovered PHA.
Bacteria
;
Fungi
3.Isolated stromal type corneal graft rejection, a case report
Sudesh Kumar ARYA ; Hemlata GUPTA ; Harsh, MOHAN ; Sunandan SOOD
International Eye Science 2011;11(1):6-7
penetrating keratoplasty was done.Isolated stromal graft rejection was noticed 3 weeks after penetrating keratoplasty,which was confirmed on histopathology.Repeat penetrating keratoplasty 6 months later also had same fate.Diagnosis and management of isolated stromal graft rejection is a very challenging situation.
4.Biosynthesis and Lipase-Catalysed Hydrolysis of 4-Hydroxybutyrate-Containing Polyhydroxyalkanoates from Delftia acidovorans
Diana Hooi-Ean Ch’ng ; Wing-Hin Lee ; Kumar Sudesh
Malaysian Journal of Microbiology 2012;8(3):156-163
Aims: Polyhydroxyalkanoates (PHA) having various molar fractions of 4-hydroxybutyrate has been successfully
synthesized by Delftia acidovorans.
Methodology and results: The monomer compositions of the PHA were varied by cultivating the bacterium in a mixture
of 1,4-butanediol and sodium valerate, γ-butyrolactone and sodium valerate as well as 4-hydroxybutyric acid and sodium
valerate, which resulted in the production of PHA terpolymers. Although the highest terpolymer content achieved was only 57 wt% of the dry cell weight, the 4HB molar fractions can be regulated from 2-50 mol% when culture conditions such as initial pH, inoculum concentration and aeration were varied. The in vitro degradation of [P(3HB-co-50 % 4HB)]synthesized by D. acidovorans were also studied by monitoring the erosion rate of the copolymer in aqueous solutions of
lipases (Lipase A ‘Amano’ 12 and Newlase F). Results have shown that the types of lipases, concentration of lipase
solution and pH of the buffer solution influenced the degradation rate of the PHA copolymer.
Conclusion, significance and impact of the study: The overall results have shown that D. acidovorans is a very
promising strain for the production of 4HB containing PHAs with specific compositions which are very suitable to be tailor made into biodegradable and biocompatible materials for medical applications.
5.Waste cooking oil as substrate for biosynthesis of poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate): Turning waste into a value-added product
Hanisah Kamilah ; Takeharu Tsuge ; Tajul Aris Yang ; Kumar Sudesh
Malaysian Journal of Microbiology 2013;9(1):51-59
Aims: Improper disposal of domestic wastes, such as waste cooking oil (WCO), contributes to the deterioration of the
environment and may lead to health problems. In this study, we evaluated the potential of plant-based WCO as a carbon source for the commercial biosynthesis of the bio-plastics, poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate). The consumption of WCO for this purpose would mitigate their pollution of the environment at the same time.
Methodology and Results: WCO collected from several cafeterias in USM was tested as the carbon source for
polyhydroxyalkanoates (PHA) production. A selection of suitable nitrogen source was first conducted in order to obtain an acceptable number of dry cell weight (DCW) and PHA content. Urea was found to be a suitable nitrogen source for the two bacterial strains used in our study, Cupriavidus necator H16 and its transformed mutant, C. necator PHB¯4 harboring the PHA synthase gene of Aeromonas caviae (PHB¯4/pBBREE32d13). With WCO as the sole carbon source, C. necator H16 yielded a relatively good dry cell weight (DCW=25.4 g/L), with 71 wt% poly(3-hydroxybutyrate) P(3HB) content. In comparison, the DCW obtained with fresh cooking oil (FCO) was 24.8 g/L. The production of poly(3
hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)] from WCO by the transformant C. necator PHB¯4 was
comparable, yielding a DCW of 22.3 g/L and P(3HB-co-3HHx) content of 85 wt%. Lipase activities for both bacterial
strains reached a maximum after 72 h of cultivation when time profile was conducted.
Conclusion, significance and impact of study: The use of WCO as a carbon source in the biosynthesis of the bioplastic, PHA, turns a polluting domestic waste into a value-added biodegradable product. This renewable source
material can thus be exploited for the low cost production of PHA.
6.Screening of bacteria for PHA production using waste glycerol as carbon source and the ability of new strain to produce P(3HB-co-3HV) copolymer
Khansaa Badie Al-Kaddo ; Kumar Sudesh ; Mohd Razip Samian
Malaysian Journal of Microbiology 2016;12(3):245-253
Aims: This study is focused on the isolation, characterization and screening of new bacterial strains isolated from soil
and wastewater samples that are able to produce PHA utilizing waste glycerol as sole carbon source in order to create
useful products from waste glycerol and at the same time reduce the PHA production cost. A new isolate, Burkholderia
contaminans Kad1 strain was investigated for its ability to biosynthesize PHA copolymers containing 3HV monomers
from waste glycerol and 3-hydroxyvalerate (3HV) precursors.
Methodology and results: PHA producing bacteria were screened using Nile Red and 1% of Nile Blue method. The
presence of PHA granules was detected using phase contrast and fluorescence microscopy. Burkholderia contaminans
Kad1, one out of 23 positive samples, was selected for further study because of its ability to produce high PHA content
(47 wt%) and dry cell weight (DCW), (4.2 g/L) when waste glycerol 2% (v/v) was used as the sole carbon source. The
16S rDNA and the PHA synthase gene were sequenced and the PHA produced was confirmed by NMR analysis. A
mixture of waste glycerol and sodium valerate fed to the culture gave rise to poly(3-hydroxybutyrate-co-3-
hydroxyvalerate) [P(3HB-co-3HV)]. The mole fraction of 3HV monomer in the co-polymer P(3HB-co-3HV) sample
analyzed using 1H NMR was 23 mol%.
Conclusion, significance and impact of study: This study demonstrated for the first time B. contaminans Kad1 was
able to use waste glycerol for PHA biosynthesis including the P(3HB-co-3HV) copolymer using a mixture of waste
glycerol with sodium valerate as the precursor.
bacteria
7.Efficient biosynthesis and recovery of polyhydroxyalkanoate
King-Sern Heng ; Su Yean Ong ; Kumar Sudesh
Malaysian Journal of Microbiology 2016;12(5):383-398
Petrochemical-derived plastics have become a source of pollution for decades, and finding alternative plastics that are
environmentally friendly has become a matter of urgency. Polyhydroxyalkanoate (PHA), a biopolyester synthesized by
microbial cells, has properties that make it suitable as a biodegradable plastic material. The diversity of PHA makes it
applicable to a wide range of products, from packaging to biomedical devices. The main challenge in commercialization
of PHA is the cost of production. Although many studies have been focused on obtaining high yields of PHA, up until
now, there is no absolute definition of efficient production of PHA, as there are many factors that could contribute to the
efficiency of a process. Efficiency in PHA recovery also contributes to the commercial viability of PHA production. This
review focuses on the efficiency of PHA biosynthesis from several aspects relating to the criteria for efficient production.
The development of new strategies for improved production, including utilization of low cost carbon sources, genetic
modification of PHA-producing microbes, and fermentation strategies are discussed here. Advances in recovery of PHA,
as well as the potential of biological recovery techniques, are also highlighted in this review.
8.Adenoviral conjunctivo-corneal epithelitis: an unusual clinical presentation of epidemic keratoconjunctivitis study
Sudesh Kumar ARYA ; Badri Prasad BADHU ; Ritu AMATYA ; V G RAMACHANDRAN ; Poonam LAVAJU
International Eye Science 2009;9(8):1444-1447
Adenoviral keratoconjunctivitis is caused by adenovirus serotypes 8,19,37.Typical signs of adenoviral con-junctivitis include preauricular lymphadenopathy, conjunc-tival hyperemia, chemosis, subconjunctival hemorrhage and follicular conjunctival reaction. Corneal involvement in adenoviral keratoconjunctivitis is variable. Most patients have a diffuse, fine, superficial keratitis with focal, elevated, punctate epithelial lesions which become subepithelial opacities later. We had a 35 years old male who had unusual clinical presentation of adenoviral conjunctivitis in the form of conjunctivo-corneal epithelitis which has not been described in the literature.Patient was managed successfully by conserva-tive treatment alone. Conjunctivo-corneal epithelitis can be unusual clinical presentation of adenoviral kerato-conjunctivitis.
9.Knowledge and Practice on Injection Safety among Primary Health Care Workers in Kaski District, Western Nepal
Sudesh Gyawali ; Devendra Singh Rathore ; P Ravi Shankar ; Vikash Kumar Kc ; Nisha Jha ; Damodar Sharma
Malaysian Journal of Medical Sciences 2016;23(1):44-55
Background: Unsafe injection practice can transmit various blood borne infections. The aim of this study was to assess the knowledge and practice of injection safety among injection providers, to obtain information about disposal of injectable devices, and to compare the knowledge and practices of urban and rural injection providers. Methods: The study was conducted with injection providers working at primary health care facilities within Kaski district, Nepal. Ninety-six health care workers from 69 primary health care facilities were studied and 132 injection events observed. A semi-structured checklist was used for observing injection practice and a questionnaire for the survey. Respondents were interviewed to complete the questionnaire and obtain possible explanations for certain observed behaviors. Results: All injection providers knew of at least one pathogen transmitted through use/re-use of unsterile syringes. Proportion of injection providers naming hepatitis/jaundice as one of the diseases transmitted by unsafe injection practice was significantly higher in urban (75.6%) than in rural (39.2%) area. However, compared to urban respondents (13.3%), a significantly higher proportion of rural respondents (37.3%) named Hepatitis B specifically as one of the diseases transmitted. Median (inter-quartile range) number of therapeutic injection and injectable vaccine administered per day by the injection providers were 2 (1) and 1 (1), respectively. Two handed recapping by injection providers was significantly higher in urban area (33.3%) than in rural areas (21.6%). Most providers were not aware of the post exposure prophylaxis guideline. Conclusion: The knowledge of the injection providers about safe injection practice was acceptable. The use of safe injection practice by providers in urban and rural health care facilities was almost similar. The deficiencies noted in the practice must be addressed.
Health Personnel
;
Injections
10.Biosynthesis of P(3HB-co-3HV-co-3HHp) terpolymer by Cupriavidus necator PHB4 transformant harboring the highly active PHA synthase gene of Chromobacterium sp. USM2
Devi-Nair Rathi ; Elin Persson Jutemar ; Frans H. J. Maurer ; Kumar Sudesh
Malaysian Journal of Microbiology 2013;9(2):140-146
Aims: This study evaluates potentials of Cupriavidus necator PHB4 transformant harboring the highly active
polyhydroxyalkanoate synthase gene (phaC) of a locally isolated Chromobacterium sp. USM2 for its ability to
incorporate 3-hydroxyheptanoate (3HHp) monomer.
Methodology and results: A mixture of fructose and sodium heptanoate fed to the culture gave rise to poly(3-
hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyheptanoate), [P(3HB-co-3HV-co-3HHp)] terpolymer synthesis, with
traces of 3HHp monomers confirmed through gas chromatography (GC), proton (1H) and carbon (13C) NMR spectra.
Conclusion, significance and impact of study: This study has revealed that the PHA synthase of Chromobacterium
sp. USM2 has a broad range of substrate specificity. The synthase is able to polymerize 3-hydroxyalkanoate monomers
having 4–7 carbon atoms.