Aims: Isolation of novel alginate degrading bacteria for the disposal of seaweed waste in composting process.
Methods and Results: Decomposition of alginate polymers was checked by the 3,5‐dinitrosalicylic acid (DNS) method for reducing sugar, and absorbance at 235 nm for unsaturated sugar. A bacterium A7 was isolated from wakame compost and confirmed to belong to the genus Gracilibacillus by partial 16S rDNA analysis. The optimum condition for the growth of A7 in a medium containing 5 g l−1 of sodium alginate is as follows: pH, 8·5–9·5; NaCl, 0·5 mol l−1; temperature, 30°C and polypeptone as nutrient content, 2–5 g l−1. In a laboratory‐scale composting experiment, the alginate content in wakame compost decreased to 14·3% after 72 h of composting from an initial value of 36%, indicating the effectiveness of alginate decomposition of A7 in wakame composting.
Conclusions: The bacterium A7 was found to be alginate lyase‐producing in genus Gracilibacillus and effective in degrading alginate to oligosaccharides in wakame during composting process.
Significance and Impact of the Study: Development of new methods for the disposal of marine wastes and production of functional products.
A collaborative study was conducted to evaluate an indirect enzymatic method for the analysis of fatty acid esters of 3-monochloro-1,2-propanediol (3-MCPD), 2-monochloro-1,3-propanediol (2-MCPD), and glycidol (Gly) in edible oils and fats. The method is characterized by the use of Candida rugosa lipase, which hydrolyzes the esters at room temperature in 30 min. Hydrolysis and bromination steps convert esters of 3-MCPD, 2-MCPD, and glycidol to free 3-MCPD, 2-MCPD, and 3-monobromo-1,2-propanediol, respectively, which are then derivatized with phenylboronic acid, and analyzed by gas chromatographymass spectrometry. In a collaborative study involving 13 laboratories, liquid palm, solid palm, rapeseed, and rice bran oils spiked with 0.5-4.4 mg/kg of esters of 3-MCPD, 2-MCPD, and Gly were analyzed in duplicate. The repeatability (RSD r ) were < 5% for five liquid oil samples and 8% for a solid oil sample. The reproducibility (RSD R ) ranged from 5% to 18% for all oil samples. These RSD R values were considered satisfactory because the Horwitz ratios were ≤ 1.3% for all three analytes in all oil samples. This method is applicable to the quantification of 3-MCPD, 2-MCPD, and Gly esters in edible oils.
In this note, we present an alternative in situ approach to determine the phase transformation temperatures of sputter deposited NiTi based shape memory thin films atop a substrate. Reflection in three thin films upon thermal cycling was measured with a reflection spectrometer in a wavelength range from 360 nm to 2 µm. Subsequently, the relationship of the reflection change versus temperature was obtained, which shows obvious hysteresis, clear evidence of the phase transformation. Hence, the transformation temperatures were determined and then compared with the result of the differential scanning calorimeter test; good agreement was observed. Additionally, we started modeling the phenomenon by identifying and quantitatively estimating four potential contributors to the change of reflection during phase transformation in deposited shape memory thin films.
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