Sodium hypochlorite digestion

Another method for extraction of PHB is by using sodium hypochlorite digestion method. With this method, 86% purity was observed with R. eutropha and 93% purity with E. coli. One of the major drawbacks of this method is that it causes degradation of PHB resulting in 50% reduction in molecular weight. 

Sodium hypochlorite was first used by Williamson and Wilkinson (1958) to isolate PHB granules from Bacillus cereus. However, sodium hypochlorite digestion of NPCM resulted in the lysis of cells without affecting the PHB. Sodium hypochlorite purification method was affecting the sudanophilic properties and molecular weight of the polymer granules. 

The method of pure polymer recovery from the biomass prior to characterization can influence the molecular weight of the polymer significantly. Extraction of PHB-bacterial cells with organic solvents yields polymers with higher molecular weight compared to sodium hypochorite treatment [44-46]. Pretreatment of the biomass with a surfactant prior to hypochlorite digestion... 

A 4.37-mg sample of protein was chemically digested to convert its nitrogen into ammonia and then diluted to 100.0 mL. Then 10.0 mL of the solution were placed in a 50-mL volumetric flask and treated with 5 mL of phenol solution plus 2 mL of sodium hypochlorite solution. The sample was diluted to 50.0 mL, and the absorbance at 625 nm was measured in a 1.00-cm cuvet after 30 min. For reference, a standard solution was prepared from... 

A latex of poly(/3-hydroxyoctanoate) can be obtained from the bacterium Pseudomonas oleovorans grown on sodium octanoate at a high cell density (22). In the course of purification sodium hypochlorite was used. It was observed that latex stabilization occurred spontaneously due to the persistence around the polymer granules of the murein sacculus, which envelopes the bacterial ceU. It was shown that the optimal conditions for the bacteria digestion correspond to a sodium h ochlorite concentration of 21-26 mmolg. ... 

The common chemical methods for extraction of PHB are solvent extraction, chemical digestion using sodium hypochlorite, sodium hypochlorite and chloroform, surfactants, surfactant hypochlorite digestion, surfactant chelate digestion, chelate hydrogen peroxide treatment, selective dissolution of nonpolymer cell mass by proton etc. 

A classic method is to digest the PHB-containing cell culture with sodium hypochlorite and measure the turbidity of the suspension produced by release of the polymer granules. Alternatively the polymer can be extracted into chloroform solution and its infrared absorbance at 1728 cm determined quantitatively. Another spectroscopic method involves hydrolysing and dehydrating the polymer to crotonic acid with concentrated sulphuric acid and assaying this by conventional quantitative UV analysis. ... 

Sodium hypochlorite Sulfamic acid Sulfite cooking liquor Sulfite digester acid (calcium bisulfite + sulfur dioxide)... 

PHA recovery process was developed to obtain the benefits of both digestion methods using sodium hypochlorite and chloroform as solvent extraction. The combined method makes three separate phases, including hypochlorite solution at the upper phase, NPCM and undisrupted cells at... 

The use of dispersions of sodium hypochlorite and chloroform for simultaneous differential digestion of NCPM and migration of the released PHB, which is hydrophobic, into the organic phase. [194]. The authors used the method on recovery of PHB from both R. eutropha and a PHB-producing recombinant strain of E. coli [127]. 

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