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.
Phytase activity and growth of anaerobic rumen bacterium, Mitsuokella jalaludinii were investigated by semi-solid
state fermentation. Carbon source (rice bran, yam and cassava), nitrogen sources (soya bean, offal meal, fish meal and
feather meal) and growth factors (hemin, L-cysteine hydrochloride and minerals) were evaluated in a one-factor-at-atime
approach. Rice bran and fish meal produced better growth and phytase enzyme activity. The removal of L-cysteine
hydrochloride and minerals significantly decreased (p<0.05) phytase activity from 1178.72 U to 446.99 U and 902.54
U, respectively. The response surface methods (RSM) was conducted to optimize the phytase production and the results
showed the combination of 7.7% of rice bran and 3.7% of fish meal in semi-solid state fermentation gave the highest
phytase activity. Maximum phytase production and optimum growth of bacteria were detected at 12 h incubation in both
MF medium (control) and agro-medium. In this agro-medium, M. jalaludinii produced 2.5 fold higher phytase activity
compared to MF medium.
Red dragon fruit or red pitaya is rich in potassium, fiber, and antioxidants. Its nutritional properties and unique flesh color have made it an attractive raw material of various types of food products and beverages including fermented beverages or enzyme drinks. In this study, phenotypic and genotypic methods were used to confirm the identity of lactic acid bacteria (LAB) appeared in fermented red dragon fruit (Hylocereus polyrhizus) beverages. A total of 21 isolates of LAB were isolated and characterized. They belonged to the genus of Enterococcus based on their biochemical characteristics. The isolates can be clustered into two groups by using the randomly amplified polymorphic DNA method. Nucleotide sequencing and restriction fragment length polymorphism of the 16S rRNA region suggested that they were either Enterococcus faecalis or Enterococcus durans.
Many plasmid-harbouring strains of Lactococcus lactis have been isolated from milk and other sources. Plasmids of Lactococcus have been shown to harbour antibiotic resistance genes and those that express some important proteins. The generally regarded as safe (GRAS) status of L. lactis also makes it an attractive host for the production of proteins that are beneficial in numerous applications such as the production of biopharmaceutical and nutraceutical. In the present work, strains of L. lactis were isolated from cow's milk, plasmids were isolated and characterised and one of the strains was identified as a potential new lactococcal host for the expression of heterologous proteins.
Cyclodextrin glucanotransferase (CGTase) is an extracellular enzyme which catalyzes the formation of cyclodextrin from starch. The production of CGTase using lactic acid bacterium is an attractive alternative and safer strategy to produce CGTase. In this study, we report the construction of genetically modified Lactococcus lactis strains harboring plasmids that secrete the Bacillus sp. G1 β-CGTase, with the aid of the signal peptides (SPs) SPK1, USP45 and native SP (NSP). Three constructed vectors, pNZ:NSP:CGT, pNZ:USP:CGT and pNZ:SPK1:CGT, were developed in this study. Each vector harbored a different SP fused to the CGTase. The formation of halo zones on starch plates indicated the production and secretion of β-CGTase by the recombinants. The expression of this enzyme is shown by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and zymogram analysis. A band size of ∼75 kDa corresponding to β-CGTase is identified in the intracellular and the extracellular environments of the host after medium modification. The replacement of glucose by starch in the medium was shown to induce β-CGTase production in L. lactis. Although β-CGTase production is comparatively low in NZ:SPK1:CGT, the SP SPK1 was shown to have higher secretion efficiency compared to the other SPs used in this study.