Results of a harmonized endotoxin recovery study protocol evaluation by 14 BioPhorum Operations Group (BPOG) member companies.

Significant regulatory and biopharmaceutical manufacturing attention has been recently generated regarding the inability to recover purified lipopolysaccharide in certain biopharmaceutical products, specifically those containing a chelator and surfactant. Disparate data has been generated and submitted during regulatory review. Study design is thought to significantly impact, and cause the confounding data. The BioPhorum Operations Group (BPOG) is an industry consortium of biopharmaceutical manufacturers. A BPOG team developed a collaborative experiment to determine if multiple laboratories could execute a harmonized protocol and reach equivalent conclusions. Twenty-one laboratories across fourteen different companies participated, yielding a robust study and large dataset. The experiment was successful as nearly all of the laboratories reached the same conclusions despite allowable variation in methods, suppliers, reagents, locations and analysts. The results of the study indicate a naturally occurring endotoxin analyte activity was recovered in a chelating buffer containing surfactant (citrate and polysorbate), and a buffer without surfactant (phosphate), while the purified lipopolysaccharide analyte activity was not recovered in the chelating buffer containing surfactant, but was recovered in the buffer without surfactant. Because the harmonized protocol yields consistent results across many different laboratories, the BPOG LER team recommends adoption of this protocol for use in endotoxin recovery studies.

Isolation of the phe-operon from G. stearothermophilus comprising the phenol degradative meta-pathway genes and a novel transcriptional regulator.

BACKGROUND: Geobacillus stearothermophilus is able to utilize phenol as a sole carbon source. A DNA fragment encoding a phenol hydroxylase catalyzing the first step in the meta-pathway has been isolated previously. Based on these findings a PCR-based DNA walk was performed initially to isolate a catechol 2,3-dioxygenase for biosensoric applications but was continued to elucidate the organisation of the genes encoding the proteins for the metabolization of phenol. RESULTS: A 20.2 kb DNA fragment was isolated as a result of the DNA walk. Fifteen open reading frames residing on a low-copy megaplasmid were identified. Eleven genes are co-transcribed in one polycistronic mRNA as shown by reverse transcription-PCR. Ten genes encode proteins, that are directly linked with the meta-cleavage pathway. The deduced amino acid sequences display similarities to a two-component phenol hydroxylase, a catechol 2,3-dioxygenase, a 4-oxalocrotonate tautomerase, a 2-oxopent-4-dienoate hydratase, a 4-oxalocrotonate decarboxylase, a 4-hydroxy-2-oxovalerate aldolase, an acetaldehyde dehydrogenase, a plant-type ferredoxin involved in the reactivation of extradiol dioxygenases and a novel regulatory protein. The only enzymes missing for the complete mineralization of phenol are a 2-hydroxymuconic acid-6-semialdehyde hydrolase and/or 2-hydroxymuconic acid-6-semialdehyde dehydrogenase. CONCLUSION: Research on the bacterial degradation of aromatic compounds on a sub-cellular level has been more intensively studied in gram-negative organisms than in gram-positive bacteria. Especially regulatory mechanisms in gram-positive (thermophilic) prokaryotes remain mostly unknown. We isolated the first complete sequence of an operon from a thermophilic bacterium encoding the meta-pathway genes and analyzed the genetic organization. Moreover, the first transcriptional regulator of the phenol metabolism in gram-positive bacteria was identified. This is a first step to elucidate regulatory mechanisms that are likely to be distinct from modes described for gram-negative bacteria.