Microbiological tests organic chemicals

In more recent times chemically defined basal media have been elaborated, on which the growth of various lactic acid bacteria is luxuriant and acid production is near-optimal. The proportions of the nutrients in the basal media have been determined which induce maximum sensitivity of the organisms for the test substance and minimize the stimulatory or inhibitory action of other nutrilites introduced with the test sample. Assay conditions have been provided which permit the attainment of satisfactory precision and accuracy in the determination of amino acids. Experimental techniques have been provided which facilitate the microbiological determination of amino acids. On the whole, microbiological procedures now available for the determination of all the amino acids except hydroxy-proline are convenient, reasonably accurate, and applicable to the assay of purified proteins, food, blood, urine, plant products, and other types of biological materials. On the other hand, it is improbable that any microbiological procedure approaches perfection and it is to be expected that old methods will be improved and new ones proposed by the many investigators interested in this problem. 

Regular monitoring of the process water, including at the point of use, for chemical and microbiological quality. The sample size and test method employed should be capable of detecting the presence of low levels of indicator organisms, e.g. Pseudomonas. 

Table 32.3 summarizes the chemical analysis results for nine heaps at the end of 177 days. Two heaps were excluded from the assessment due to the presence of a mixed organic/inorganic pollution. Of special interest was TPH in C25-C35, which could not be remedied by microbiological methods. In all heaps, the different types of petroleum product responded to ECGO. TPH after 177 days of treatment was substantially below regulatory cleanup levels. As to PAH, the concentrations prior to the test were already below the cleanup levels and are reproduced only for purposes of completeness. 

Botsford, 1. L. 2000a. A comparison of altemalive tests for toxic chemicals. To be submitted ATLA journal. Botsford, 1. L. 2000b. Role of EDTA in a simple method for determining toxicity using a bacterial indicator organism. World Journal Microbiology and Biotechnology, in press. 

Section V on Testing in Environments (H. Hack, Section Editor) includes chapters on outdoor and indoor atmospheres, seawater, fresh water, soils, concrete, industrial waters, industrial chemical, petroleum, high-temperature gases, organic liquids, molten salts, liquid metals, corrosion inhibitors, in-vivo, and microbiological effects. Each chapter provides a descriptive overview of the environment and factors and variables affecting corrosion rates and mechanisms. 

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