BUKU ABSTRAK - Universiti Putra Malaysia

Science, Technology & Engineering
Comamonas putranensis Sp. nov., a Novel Bacterium Producing
Polyhydroxyalkanoates from Palm Oil Mill Effluent
Prof. Dr . Mohd. Ali Hassan
Mohd. Rafein Zakaria, Suraini Abd. Aziz, Farinazleen Mohd. Ghazali, Wakisaka Minato and Yoshihito Shirai
Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 7590; alihas@biotech.upm.edu.my
The bacterial strain EB 172, isolated from digester treating palm oil mill effluent, was investigated by
polyphasic taxonomic approach. The cells were rod-shaped, Gram-negative, non-pigmented, non-spore-forming
and non-fermentative. Phylogenetic analyses using the 16S rRNA gene sequence showed that the strain was
placed in the cluster of genus Comamonas; its closest neighbours were the type strains C. terrigena (96.8%),
C. koreensis (93.4%), C. composti (92.9%), and C. kerstersii (91.1%). The ability of C. putranensis to produce
polyhydroxyalkanoates (PHA) when supplied with organic acids made this bacterium unique in the Comamonas
species. The bacterial strain was clearly distinguished from all of the existing strains using phylogenetic analysis,
fatty acid composition data and a range of physiological and biochemical characteristics. The DNA G+C content
of the genomic DNA was 59.1 mol%. It is evident from the genotypic and phenotypic data that strain Comamonas
putranensis represents a novel species in the genus Comamonas, for which the name Comamonas putranensis
Sp. nov. is proposed.
Keywords: palm oil mill effluent, comamonas sp., polyhydroxyalkanoates, isolation, screening
Natural-based Mica Network as Nanoreactor for Enzymes in Chiral Syntheses
Prof. Dr. Mohd. Basyaruddin Abdul Rahman
Uswatun Hasanah Zaidan, Siti Salhah Othman, Mahiran Basri, Emilia Abdulmalek, Bimo Ario Tejo and Abu
Bakar Salleh
Faculty of Science, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 6798; basya@science.upm.edu.my
Mica is an economical carrier of clay material for immobilisation of lipase and has been potentially utilised
for this purpose. Instead of its low cost, industrial application of lipase requires efficient methods to immobilise
the enzyme, yielding a biocatalyst with high activity and stability compared to free lipase. Natural aluminosilicate
of mica from the land area of Gua Musang, Kelantan (Malaysia) was physico-chemically characterised by
performing a good crystallinity, high surface area and possess uniformity of mesoporous material. Natural mica
was modified either by acid treatment, grafting with aminopropyl-, octyl-, vinyl-, mercapto- and glycidoxytriethoxysilanes,
and activation of pre-treated support with glutaraldehyde (Glu). The modified micas were used
for immobilisation of lipase from Candida rugosa (CRL). Under optimal conditions, high protein loadings and
specific activities of more than 8.0 mg/g-support and 90.0 U/mg, respectively, whereby their specific activities
increased up to more than 2.5 fold as compared to free lipase. Activity of the lipase was determined by esterification
of fatty acid sugar esters in organic media with more than 70%. Proper modification of mica improves its quality
for lipase immobilisation showing promising action as bio-nanoreactor for many organic syntheses especially the
production of the high value-added of chiral isomers.
Keywords: Mica, clay, lipase, biocatalyst, nanoreactor, immobilised enzyme
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