A novel DNA biosensing platform was designed by the functionalization of iron oxide (Fe3O4)
with the carboxylic group via capping agent, mercaptopropionic acid (MPA) and conjugated
with nanocellulose crystalline (NCC) surface modified with surfactant cetyltrimethylammonium
bromide (CTAB) to assist in the DNA sensing capability. The product of nanocomposites
compound was drop-casted on screen printed carbon electrode (SPCE). Characterization by field
emission scanning electron microscope (FESEM) and energy dispersive X-Ray (EDX)
spectroscopy showing that carboxyl functionalized iron oxide (COOH-Fe3O4) can be hybridized
with NCC-CTA+ via electrostatic interaction.
In this paper, the syntheses of kojic acid esters via chemical and enzymatic methods are
reviewed. The advantages and disadvantages of chemical process in term of process, safety and
efficiency are discussed. In enzymatic process, the significant process parameters related to the
synthesis of kojic acid esters such as the lipases, solvent, temperature and water content are
highlighted. Possible enzymatic synthesis using solvent and solvent-free system taking into
consideration of the difference in these systems involving cost, lipase reusability and efficiency
is comparatively reviewed. The possible approach for large scale production using various
enzyme reactor designs is also discussed and re-evaluated.
Biosurfactants are surface active compounds and amphiphatic in nature which consist of
hydrophilic head and hydrophobic tail accumulating at the interphase of two immiscible liquid
with different polarity. A study was conducted to investigate the effectiveness of sunflower oil in
the production of rhamnolipids (RLs) by locally isolated Pseudomonas aeruginosa in shake flask
fermentation. In this process, four different fermentation treatments were done for seven days at
30°C and 180 rpm. Sampling was carried out in time intervals of 24 h followed by monitoring of
cell growth and biosurfactants production. Colorimetric Orcinol analysis was used for
determination of RLs concentrations (g/L). The RLs were studied for emulsification activity
using emulsification index (E24%) methods. In addition, oil displacement activity and thermal
stability were also studied (4-120°C). All treatments allow the growth of P. aeruginosa and the
utilization of sunflower oil as carbon source and glucose as growth initiator were observed to be
the best strategy for maximum RLs production. The maximum RLs production was achieved
after 120 h with 3.18 g/L of RLs. Diesel shows the highest emulsification activity among the
substrate tested ranging from 55.56% - 60.00%. The oil displacement activity was corresponding
to RLs concentration with stability up to 120°C (for 60 min). Therefore, from this research a
good potential of RLs that may provide good application for industry were produced.
Despite the continued effort globally made to control the growing case of Tuberculosis (TB), it
continues to be regarded as the second deadliest disease after the HIV. There are various
methods developed to diagnose TB, most of which having the criteria of sensitive, selective,
cheap and portable to be used in robust applications. Even with the advancement in medication,
the important keys including early stage diagnosis is yet to be considered. In diagnosing TB, the
only technique remained as the gold standard method is the culturing method, which is the Acid
Fast Bacilli (AFB) staining. On the other hand, molecular technique utilising Polymerase Chain
Reaction (PCR) assay is preferred as a non-culturing method. Additionally, as molecular
techniques become advanced, real-time PCR or quantitative PCR (qPCR) using multiple probes
in one shot has raised interest among researchers, because it can skip the process of gel
electrophoresis. Recently, researchers have been working on electrochemical DNA sensors
which are sensitive, selective, rapid, cheap and can meet with point of care (POC) testing
requirements to diagnose TB.