Acid In Fermentation Media Research Articles

Phosphate Solubilizing and Phytate Degrading Streptomyces Isolates Stimulate the Growth and P Accumulation of Maize (Zea mays) Fertilized with Different Phosphorus Sources

Actinobacteria are involved in many soil processes related to plant growth, including the secretion of various bioactive products and nutrient cycling. The aim of this study was to characterize the plant growth promoting traits (phosphate solubilizing activity, phytate degradation ability and indolic compounds production, and organic acids secretion) of seven actinobacteria isolates and evaluate the effect of two selected rhizospheric Streptomyces on growth and phosphorus content of maize in presence of different phosphorus (P) sources (tri-calcium phosphate, triple super phosphate and calcium phytate). Phylogenetic analysis of partial 16S rRNA sequences showed that the Streptomyces isolates were clustered in two distinct separated groups. All Streptomyces isolates produced 2-ketogluconic acid and oxalic acid in fermentation medium supplemented with inorganic P sources, while in the presence of phytate, all isolates secreted 2-ketogluconic acid and malic acid. All the isolates were able to release inorganic P from insoluble phosphate sources and this behavior was negatively correlated with pH reduction. Phytate degradation raged from 1.65% to 95.2%, and total indole compound production ranged from 6.3 to 27.8 µg ml−1. The shoot dry weight, root dry weight, plant height, chlorophyll content and tissue P concentration were significantly (p < 0.05) increased by both inoculations with Streptomyces isolates and by the addition of different phosphorus sources, compared to their appropriate controls. The inoculation of Streptomyces isolates resulted in a significant increase in plant phosphorus content from different phosphate sources. Streptomyces sp. UTMC 1478 (Streptomyces sp. 63) and Streptomyces sp. 47 were suitable inoculants for increasing maize growth and P from soil amended with different phosphorus sources, indicating their potential use as plant growth-promoting phospho-bacteria.

Automated measurement of pH-dependent solid-liquid equilibria of itaconic acid and protocatechuic acid

Crystallization is a highly selective unit operation capable of separating target molecules from complex media. Its design requires precise solid-liquid equilibrium (SLE) data. The SLE of platform chemicals like carboxylic acids in complex aqueous media depends on temperature, pH value as well as on present side components, but predominantly, only the solubility for different temperatures is reported. This work presents a novel automated method for the determination of the pH- and temperature-dependent SLE in complex media using readily available laboratory equipment. Taking the example of itaconic acid, the pH-dependent solubility for different temperatures is measured and validated with results obtained from the classic excess solid method along with literature data. Using the automated setup, the influence of different loadings of sodium chloride on the SLE of itaconic acid is investigated and a correlation between solubility and concentration of the electrolyte is derived. The SLE data acquired for protocatechuic acid in fermentation medium demonstrates the applicability of the method for the determination of comprehensive SLE in multicomponent mixtures without the requirement of specific analytical methods for the target compound. The resulting SLE data can be used for a more precise design and techno-economic evaluation of crystallization processes in biotechnological production routes.

Triphasic esterification of butanol and butyric acid in fermentation media

Abstract Butanol and butyric acid produced from acetone-butanol-ethanol (ABE) fermentation can be used to produce butyl butyrate, an important fragrance ester. However, low levels of butanol and butyric acid need to be purified from culture media first with energy-intensive distillation processes. In this study, a triphasic (organic/aqueous/fluorous) system is developed to esterify butanol and butyric acid in spent culture media into butyl butyrate directly without purification. The produced butyl butyrate forms a distinct organic phase floating on top and can then be separated easily. In a model system containing 37.1 g/L of butanol and 44.1 g/L of butyric acid, 57% of the butanol is converted to butyl butyrate after 8 h of esterification. With multiple cycles of esterification and product removal, butanol conversion can be further increased to 86%. When spent culture medium containing 7.12 g/L of butanol and 4.81 g/L of butyric acid is used for esterification, 38% of butanol (0.36 mmol) is consumed and 0.33 mmol of butyl butyrate is produced. However, when ABE fermentation and esterification are carried out simultaneously, only 0.042 mmol of butyl butyrate is produced, probably due to the incompatible pH requirements for cell growth (pH 5–7) and esterification (pH 2–3).

Enhanced Production of Bioactive Sophorolipids by &lt;i&gt;Starmerella bombicola&lt;/i&gt; NRRL Y-17069 by Design of Experiment Approach with Successive Purification and Characterization

In present study, fermentative production of Sophorolipids (SLs) by Starmerella bombicola NRRL Y-17069 that have antibacterial activities was optimized. The media components like glucose, yeast extract and urea were critical components in the microbial growth and formation of SL moiety. The secondary carbon; oleic acid supports the formation of SLs. These components were optimized for maximum production of total SLs which have potential application. Optimization by one factor at-a-time method, glucose and yeast extract were found to be best sources for maximum production of SLs (g/L), 20.94 and 32.1 resp. Oleic acid (100 g/L) gave maximum production of 54.16 g/L with 54 % conversion of added oleic acid in fermentation media indicating fed batch operation is best for SLs production. Total sophorolipids formed were purified and 98.1% lactonic form was obtained by crystallization. Characterization of lactonic SLs by FT-IR, NMR and attached fatty acid moiety was confirmed by GCMS.

Determination of citric acid in fermentation media by pyrolysis mass spectrometry

Rapid and sensitive determination of citric acid in fermentation media by pyrolysis mass spectrometry (Py–MS) is proposed. Owing to high specificity of this method, distinguishing the citric acid from the matrix and by-products formed in the Krebs cycle is possible. Selected ion monitoring (SIM) mode is used for quantitative measurements, in which mass to charge ( m/ z) values of 175 of citric acid and 138 of 3-nitroaniline as internal standard are chosen. Limit of detection (LOD) for this method has been found to be 1 ng ml −1 and the linear working range was 10 ng ml −1–100 mg ml −1. Relative standard deviation (R.S.D.) of the method for five replicates was 0.84%. Results of Py–MS are compared with those obtained by UV–vis spectrophotometric method. Also, factor analysis is used for evaluating the influence of pH, molasses concentration, time and shaker intensity on the production of citric acid by Aspergillus niger.

Determination of phenylpropionic acid in fermentation medium by chromatographic techniques

Phenylpropionic acid was determined in the fermentation medium by gas chromatography using an internal standard and by reversed phase high-performance liquid chromatography. The two methods were evaluated by using the standard quantitative criteria employed in analytical chemistry.

Direct thin-layer densitometric determination of citric acid in fermentation media

A new method for determining citric acid in fermentation media is proposed. The procedure involves direct application of properly diluted culture medium filtrate to a TLC plate, subsequent chromatographic separation and coloration of citric acid spots, and densitometric evaluation. By this method, citric acid can be determined with a good accuracy in the range from 1–5 μg/μl. The densitometric analysis proved to be of high reproducibility with a relative standard deviation from 2–4% and a 99.7% recovery efficiency for citric acid added to the culture medium.

Quantitative estimation of gibberellic acid by paper chromatography

A method for the quantitative determination of gibberellic acid in fermentation media, using descending paper chromatography in butylacetate-water is described. A sample is adjusted to pH 2.5–3.0, extracted with n-butanol, and 0.05 ml. organic layer is spotted on Chromatographic paper. After equilibration of the atmosphere in the jar, the chromatogram is developed in butylacetate saturated with water, for 7 hours, and the solvent is allowed to drip off the bottom of the sheet. Detection is carried out by spraying with a 3% solution of sulphuric acid in methanol and after drying the paper, spots with blue u.v. fluorescence are observed. The area of the spots is evaluated with the aid of a calibration curve, plotted from values of standards corresponding to 20, 60 and 120 μg. gibberellic acid. The error of estimation is ±10–15% when estimations are carried out carefully. The lowest limit of sensitivity is 5 μg.

Determination of Citric Acid in Fermentation Media and Biological Materials

Determination of Citric Acid in Fermentation Media and Biological Materials