Biotransformation of various carbon sources to kojic acid by cell-bound enzyme system of A. flavus Link 44-1

The ability of cell-bound enzyme of Aspergillus flavus Link 44-1 for production of kojic acid was studied in resuspended cell system. Cell material was produced in batch fermentation using 2 L stirred tank fermenter. The cell mycelia were then resuspended into 250 mL shake flask containing various carbon sources solution. Among the carbon sources tested, glucose gave the highest kojic acid yield based on carbon consumed (0.365 g/g) followed by sucrose (0.279 g/g), starch hydrolysate (0.212 g/g) and fructose (0.195 g/g). The rate of biotransformation was increased with increasing mycelial cell. Kojic acid production was also varied with different glucose and sucrose concentrations. The highest production was obtained at 100 g/L glucose and 100 g/L sucrose with a final kojic acid concentration of 45.3 and 33.4 g/L, respectively. The rate of biotransformation of glucose and sucrose to kojic acid followed the Michaelis–Menten equation, suggesting that the biotransformation rate vary with substrate concentration similar to the behaviour of many enzymes reaction

The Assessment of Plastic Materials for Monitoring the Moisture, Colour, Pungency and Rancidity of 'Chili Boh'

'Chili Boh', which is a slurry of Capsicum annum was prepared in the laboratory and then packaged in heat sealed pouches of polypropylene (PP), low density polyethylene (LDPE), a laminate of polypropylene, cellophane and polyethylene (PPICPPILDPE) and a laminate of oriented polypropylene- polyethylene (OPPIPE). The package samples were stored at ambient temperature and analysed periodically to assess any changes in its moisture, colour, pungency and flavour. Colour was found to be the limiting factor in the shelf-life of the product. The pungency and the flavour (related to degree of rancidity) of the samples were relatively stable up to six weeks. Slight loss of moisture was observed upon storage. PPICPPILDPE and OPPIPE proved to be equally acceptable in maintaining the studied qualities of 'Chili Boh' for up to four weeks. However, OPPIPE is recommended for commercial use due to its low unit cost

The morphology and structure of red pigment producing fungus: monascus purpureus

Thered pigment producing, ascospore forming fungus Monascus purpureuswas obtained by monospore isolation and maintained on potato dextrose agar at 32°C for 7 days. M. purpureusproduces compact colonies of mycelia and accumulates large quantities of red pigment. Here we aimed to describe this newly isolated red pigment producing fungus using biochemical and microscopy technique. A newly isolated red pigment producing fungus from local red fermented rice was identified using Microbial Identification System based on fatty acids profiles.The growth, morphology, and structure of M. purpureuswere characterized by Scanning Electron Microscopy (SME). We found that M. purpureusreproduces sexually (by the formation of cleistothecium with ascospores) and asexual (by the formation of conidia). In Monascusspecies, the formation of either asexual or sexual spores appears to be an effective growth strategy. On the basis of biochemical and all morphological investigations it could be concluded that the new strain isolated from red fermented rice belongs to species M. purpureus, labeled as M. purpureus FTCC 5391

Comparison of expression systems for the production of human interferon-a2b.

The production of human interferon alpha2b (IFN-α2b) in two expression systems, tobacco (Nicotiana tabaccum) and Escherichia coli, was compared in various aspects such as safety, yield, quality of product and productivity. In the E. coli system, IFN-α2b was expressed under a pelB signal sequence and a T7lac promoter in a pET 26b(+) vector. The same gene was also cloned in expression plant vector (pCAMBIA1304) between cauliflower mosaic virus promoter (CaMV35S) and poly A termination region (Nos) and expressed in transgenic tobacco plants. The expression of protein in both systems was confirmed by western immunoblotting and the quantity of the protein was determined by immunoassay. The amount of periplasmic expression in E. coli was 60 µg/L of culture, while the amount of nuclear expression in the plant was 4.46 µg/kg of fresh leaves. The result of this study demonstrated that IFN-α2b was successfully expressed in periplasm of bacterial and plant systems. The limitations on the production of IFN-α2b by both systems are addressed and discussed to form the basis for the selection of the appropriate expression platform

Heterotrophic cultivation of microalgae for production of biodiesel

High cell density cultivation of microalgae via heterotrophic growth mechanism could effectively address the issues of low productivity and operational constraints presently affecting the solar driven biodiesel production. This paper reviews the progress made so far in the development of commercial-scale heterotrophic microalgae cultivation processes. The review also discusses on patentable concepts and innovations disclosed in the past four years with regards to new approaches to microalgal cultivation technique, improvisation on the process flow design to economically produced biodiesel and genetic manipulation to confer desirable traits leading to high valued lipid-bearing microalgae strains

Enzymatic saccharification of pretreated solid palm oil mill effluent and oil palm fruit fiber.

The effectiveness of various chemicals pretreatment (NaOH, HCl, NH3, HNO3 and EDTA) on the enzymatic saccharification of solid palm oil mill effluent (POME) and oil palm fruit fibre (OPFF) was investigated. The results showed that NaOH seem to be the most suitable chemical pretreatment for enhancing sugar production and the degree of hydrolysis from saccharification of OPFF. NaOH at a concentration of 2% (w/v) appears to be optimal for alkaline pretreatment of OPFF. However, chemical pretreatment of solid POME using NaOH, NH3, HNO3, HCl and EDTA was found to be ineffective in enhancing the degree of hydrolysis and sugar production as compared to chemically untreated solid POME. Autoclaving OPFF at 121°C, 15 psi for 5 minutes improved the degree of hydrolysis up to 2.4 times. However, the degree of hydrolysis was not significantly affected for solid POME under the same conditions

The performance of a glass bead shaking technique for the disruption of Escherichia coli cells

The efficacy of a simple laboratory method for cell disruption based on the shaking of glass beads on a rotary shaker was assessed in this study, via measurements of the release of total protein and interferon-α2b from E.coli. The optimum conditions for cell disruption were detected after 30 min of shaking in Tris-HCl buffer (pH 8) at 300 rpm with 1.5g of glass beads (diameter: 0.5 mm) per mL of cell suspension volume. Three test runs were conducted under the above conditions and the maximum average protein release values were determined as 3.048, 3.564, and 3.015 mg/mL, respectively. The amount of protein release was comparable to the amount of protein release in ultrasonication and glass bead vortexing procedures. The amount of interferon-α2b release in the ultrasonication, glass bead vortexing, and glass bead shaking trials were 240, 172, and 201 ng/mL, respectively. This method was shown to process between 1 and 10 mL of sample volume in a 50 mL Falcon tube without a great deal of deviation, and was able to handle in excess of 60 samples simultaneously

Improved protocol for the preparation of tetraselmis suecica axenic culture and adaptation to heterotrophic cultivation.

The effectiveness of various physical and chemical methods for the removal of contaminants from the microal-gae, Tetraselmis suecica, culture was investigated. The information obtained was used as the basis for the development of improved protocol for the preparation of axenic culture to be adapted to heterotrophic cultivation. Repeated centrifugation and rinsing effectively removed the free bacterial contaminants from the microalgae culture while sonication helped to loosen up the tightly attached bacterial contaminants on the microalgae cells. Removal of bacterial spores was accom- plished using a mixture of two antibiotics, 5 mg/mL vancomycine and 10 mg/mL neomycine. Walne medium formulation with natural seawater was preferred for the enhancement of growth of T. suecica. Adaptation of growth from photoautot- rophic to heterotrophic conditions was achieved by the repeated cultivation of photoautotrophic culture with sequential reduction in illumination time, and finally the culture was inoculated into the medium containing 10 g/L glucose, incu- bated in total darkness to obtain heterotrophic cells. Changes in the morphology and composition of T. suecica cells dur- ing the adaptation from photoautotrophic to heterotrophic condition, as examined under Transmission Electron Micro- scope, were also reported