Highly flame retardant coating consisting of starch and amorphous sodium polyborate

Mixture of starch and amorphous sodium polyborate (SPB) is found to show high flame retardancy, when its aqueous solution is deposited and dried on organic polymer materials such as polyethylene terephthalate (PET) nonwoven, rigid polyurethane (RPU) foam, and polypropylene (PP) nonwoven. The PET nonwoven (10 mm thickness) and the RPU foam (10 mm thickness) coated with the mixture endure the premixed flame of butane gas burner with length of 100 mm for more than 12 min. The PP nonwoven (0.7 mm thickness) endures the nonpremixed flame with length of 65 mm in the 45 degrees Meckel burner test for more than 2 min. The backside temperatures in the both tests remain below 130 °C. The thermal analyses and the SEM observation indicate the mechanism that the SPB foam promotes the carbonization of starch and that the carbonized layer together with the SPB foam insulate inside from oxygen and heat.     

Production of recombinant human lysosomal acid lipase in Schizosaccharomyces pombe: development of a fed-batch fermentation and purification process

A fed-batch fermentation process has been developed to enable the production of large quantities of recombinant human lysosomal acid lipase (hLAL; EC 3.1.1.13), in Schizosaccharomyces pombe, for preclinical studies as a potential enzyme therapy drug. Recombinant S. pombe, clone ASP397-21, expressed enzymatically active hLAL in the secreted form. A feedback fed-batch system was used to determine the optimal feed rate of a 50% glucose solution used as the carbon source. The feed rate of the glucose solution was calculated by a computer-aided system according to the equation; F=q(sf)(VX)/S(in) (q(sf), specific substrate feed rate [gram substrate/gram dry cell weight/h]; V, volume of culture broth [l]; X, cell density [gram dry cell weight/l]; S(in), concentration of growth limiting substrate in feed solution [gram substrate/gram feed solution]). At the time of the initial consumption of glucose in the batch-phase culture, the nutrient supply was automatically initiated by means of monitoring the respiratory quotient change. The obtained profile of the feed rate was applied to the feed forward control fermentation. Finally, the cells were grown up to >50 g dry cell weight/l, and the hLAL expression level was approximately 16,000 U/l. Expressed hLAL protein was purified in a two-step process by hydrophobic interaction and anion exchange chromatographies. Purified recombinant hLAL exhibited a 90-150 kDa broad band upon SDS-PAGE with specific activity of about 300 U/mg. After endoglycosidase H treatment, the band converged to 45 kDa, equal to the calculated molecular weight, suggesting that hLAL produced in S. pombe was hyper-glycosylated. N-terminal analysis of de-glycosylated hLAL revealed that the signal sequence of hLAL was correctly processed in S. pombe.     

Development of a method to relate the moisture content of a building material to its water activity

Subjective indicators of building dampness consistently have been linked to health, but they are, at best, semi‐quantitative, and objective and quantitative assessments of dampness are also needed to study dampness‐related health effects. Investigators can readily and non‐destructively measure the “moisture content” (MC) of building materials with hand‐held moisture meters. However, MC does not indicate the amount of the water in a material that is available to microorganisms for growth, that is, the “water activity” (A_w). Unfortunately, A_w has not been readily measurable in the field and is not relatable to MC unless previously determined experimentally, because for the same moisture meter reading, A_w can differ across materials as well as during moisture adsorption vs desorption. To determine the A_ws that correspond to MC levels, stable air relative humidities were generated in a glove box above saturated, aqueous salt solutions, and the A_w of gypsum board and the relative humidity of the chamber air were tracked until they reached equilibrium. Strong correlations were observed between meter readings and gravimetrically determined MC (r=.91‐1.00), among readings with three moisture meters (r=.87‐.98), and between meter readings and gypsum board A_w (r=.77‐.99).     

Enumeration of fungi in fruits by the most probable number method

In this study, enumeration methods for fungi in foods were evaluated using fruits that are often contaminated by fungi in the field and rot because of fungal contaminants. As the test methods, we used the standard most probable number (MPN) method with liquid medium in test tubes, which is traditionally used as the enumeration method for bacteria, and the plate-MPN method with agar plate media, in addition to the surface plating method as the traditional enumeration method for fungi. We tested 27 samples of 9 commercial domestic fruits using their surface skin. The results indicated that the standard MPN method showed slow recovery of fungi in test tubes and lower counts than the surface plating method and the plate-MPN method in almost all samples. The fungal count on the 4th d of incubation was approximately the same as on the 10th d by the surface plating method or the plate-MPN method, indicating no significant differences between the fungal counts by these 2 methods. This result indicated that the plate-MPN method had a number agreement with the traditional enumeration method. Moreover, the plate-MPN method has a little laborious without counting colonies, because fungal counts are estimated based on the number of plates with growing colonies. These advantages demonstrated that the plate-MPN method is a comparatively superior and rapid method for enumeration of fungi.     

Kluyveromyces marxianus-based platform for direct ethanol fermentation and recovery from cellulosic materials under air-ventilated conditions

Consolidated bioprocessing represents an attractive approach to converting cellulosic materials into bioethanol, yet is practically unavailable. We developed a ventilation-mediated, simultaneous ethanol fermentation and recovery system. Running the system under air-supplied conditions, apparently pure ethanol (28g) was recovered from cellobiose (100g) by growing recombinant Kluyveromyces marxianus expressing β-glucosidase.     

Characterization of d-succinylase from Cupriavidus sp. P4-10-C and its application in d-amino acid synthesis

1. Download high-res image (112KB)
2. Download full-size image