Untreated Broth Research Articles

Recovery of succinic acid from fermentation broth by forward osmosis-assisted crystallization process

In this study, osmotically driven forward osmosis (FO) was employed prior to crystallization process in the downstream recovery of bio-based succinic acid. The fermentation broth containing succinic acid was initially pretreated using activated carbon. Powdered activated carbon (PAC) showed its effectiveness for glucose, formic acid, and color removal while succinic acid concentration remained unaffected. The untreated and treated fermentation broths were then concentrated using the FO process. FO exhibited a remarkable enhancement of concentration factor (CF) by 3.9-fold for the treated broth, thus resulting in a final succinic acid concentration of 111.26 g/L. By contrast, higher flux loss and lower CF were observed for untreated broth, mainly due to the adverse effect of severe membrane fouling and cake layer formation. Succinic acid crystals were then successfully recovered from the FO-concentrated broth in the final crystallization step. The purity and yield of succinic acid crystals were 90.52% and 67.09%, respectively for treated broth. This work demonstrated the development of a feasible FO-crystallization process for the downstream recovery of bio-based succinic acid. The findings have important implications for practical applications of FO technology in the bioprocess industries.

The synergistic effect of PDT and oxacillin on clinical isolates of Staphylococcus aureus.

Staphylococcus aureus is a major pathogen in clinical microbiology. It is known to cause infections at various body sites and can be life-threatening. The development of resistance to many well-established antibiotic treatments and the prevalence of methicillin-resistant S. aureus (MRAS) among hospital patients and the general community pose challenges in treating the pathogen. The antimicrobial effect of photodynamic therapy (PDT) has been a subject of study for a long time and can offer new strategies for dealing with resistant strains. In our study, we searched for a positive synergistic relationship between PDT and the standard antibiotics used to treat S. aureus and MRSA infections. The phototoxic profile of deuteroporphyrin (DP) in both resistant and susceptible clinical strains of S. aureus was determined by plating of treated and untreated broth cultures. Electron microscopy imaging was done to explore possible sites of damage and free-radical accumulation in the cells during DP-PDT. Minimal inhibitory concentration (MIC) of oxacillin, gentamicin, vancomycin, rifampin, and fusidic acid was determined using the broth dilution method, and the checkerboard method was used to detect and evaluate the synergistic potential of DP-PDT and antibiotic combinations. A synergistic combination was further characterized using broth cultures and plating. DP-PDT using a light dose of 15 J/cm2 showed a bactericidal effect even with a small concentration of 17 μM DP. Transmission electron microscopy indicated profound damage in the cell wall and cell membrane, and the appearance of mesosome-like structures. Free radicals tend to localize in the cell membrane and inside the mesosome. No synergistic effect was detected by combining PDT with gentamicin, vancomycin, rifampin, and fusidic acid treatments. A positive synergistic effect was observed only in DP-PDT-oxacillin combined treatment using the checkerboard method. The effect was observed in clinical antibiotic-resistant isolates after DP-PDT using a light dose of 46 J/cm2 and small concentrations of DP. Oxacillin MIC decreased below 2 μg/ml in resistant strains under such conditions. Cultures which did not undergo new cycles of DP-PDT recovered their original oxacillin resistance after a few generations. PDT with porphyrins shows possible new therapeutic options in treating drug-resistant S. aureus at body sites suitable for irradiation. The synergistic effect of DP-PDT with oxacillin on clinical strains illustrates the potential of PDT to augment traditional antibiotic treatment based on cell wall inhibitors. Lasers Surg. Med. 50:535-551, 2018. © 2018 Wiley Periodicals, Inc.

The effect of antimicrobials on verocytotoxin bacteriophage transduction under bovine rumen fluid and broth conditions

AbstractThe verocytotoxin genes in verocytotoxigenicEscherichia coli(VTEC) are carried by bacteriophages, incorporated into the bacterial genome (prophage). Antibiotics may promote phage replication and release to infect other cells (transduction), thus leading to the emergence of new VTEC strains. This study investigated transduction of a verocytotoxin2-encoding bacteriophage (3538(vtx2::cat)) under laboratory conditions, including the effect of antibiotic treatments. Luria-Bertani Miller broth and rumen fluid (raw and sterilised by irradiation) were inoculated with the donor (C600φ3538(Δvtx2::cat)) and recipient (E. coli C600::kanamycinR) strains (4 log10cfu/mL) and incubated at 38°C. Antibiotic treatments (minimal inhibitory and sub-inhibitory concentrations of ampicillin, cefquinome, oxytetracycline and sodium sulfamethazine) were applied after 3 h. Samples were tested for donor, recipient, cell-free phage and transductants at times t = 0, 3, 4, 6, 27 (24 h post-antibiotic treatment) and 51 h. Free phage was detected in the untreated broth and rumen samples, as were the transductants confirmed by polymerase chain reaction. The antibiotic treatments did not significantly (P > 0.01) increase the concentrations of free phage or transductants detected. It was therefore concluded that, under laboratory conditions, the antibiotics tested did not induce bacteriophage lysis, release and infection of new bacterial cells beyond that constitutively found in the phage population.

식물근권에서 분리한 세균의 어류질병세균에 대한 항균활성 효과

Olive flounder (Paralichthys olivaceus) is an important aquaculture fish species in Jeju Island, South Korea. Due to the intensification of flounder fish farming, huge amounts of chemical antibiotics are used against several fish diseases. This has many harmful side effects on fish, as well as human consumers. Hence, an alternative to chemical antibiotic agents is needed for disease control. In this study, three strains of rhizobacteria (BRH433-2, TRH415-2, and THJ609-3) were isolated from the rhizosphere of plants. Assays of their antibacterial activity against fish pathogens, such as S. iniae, S. parauberis, V. anguillarum, and E. tarda, were performed with untreated broth culture (without cell separation), supernatant, and precipitated pellets separated by centrifugation. Among these, the cell suspension prepared from the precipitated pellet showed significant antimicrobial activity when compared with that of the untreated broth culture and centrifugal supernatant. These results indicate that the three isolated rhizobacterial strains exhibit antibacterial activity. Analysis of the 16S rDNA sequences of the BRH-433-2, THJ609-3, and TRH415-2 strains showed the highest similarity to Burkholderia gladioli (99.5%), Pseudomonas baetica (97.7%), and P. koreensis and P. baetica (98.4%), respectively. We suggest that the strains hold promise in disease management of fish.

Pretreatment of Highly Polluted Pharmaceutical Waste Broth by Wet Air Oxidation

The preoxidation of a highly polluted waste pharmaceutical fermentation broth using wet air oxidation (WAO) has been studied as a possible method for the effective removal of organics. The applied (pre)treatment method should enhance the biotreatability of the pharmaceutical fermentation broth in terms of reduced initial toxicity and higher biodegradability. Preliminary experiments in the pilot biological treatment plant were successful only at low organic loads, whereas the system collapses at higher ones. The characterization of the fermentation broth was started by common physicochemical analysis, whereas several bioassays were used to determine its impact on biological treatment plants and the environment. Toxicity prior to and after WAO was determined using the acute Vibrio fischeri test, measurement of inhibition of O2 consumption, and the Daphnia magna acute test. Ready biodegradability of the treated and untreated broth has also been assessed. WAO experiments were accomplished in the 2 L batch rea...

EFFECT OF AN OXYGEN‐REDUCING MEMBRANE FRACTION ON HELICOBACTER PYLORI

The emerging gastric pathogen Helicobacter pylori is an oxygen‐sensitive fastidious microaerophile. Culturability of this organism is rapidly lost in oxygen levels present in the atmosphere due to its morphological transformation into a viable but not culturable state. The effect of the OxyraseTM system of oxygen‐reducing membrane fragments on H. pylori was evaluated at levels ranging from 0.1 to 0.6 Units/mL in Brucella broth supplemented with 5% horse serum. Duplicate sets of OxyraseTM dilutions inoculated with H. pylori were incubated at 35C aerobically and microaerobically. At these OxyraseTM levels, a logarithmic loss of H. pylori viability was evident in the aerobic cultures. The inoculum remained recoverable for 24 h in the presence of OxyraseTM, whereas recovery of inoculum in untreated broth was greatly reduced after 8 h of aerobic incubation, and the organism was unrecoverable after 24 h. OxyraseTM‐containing broth cultures of H. pylori incubated microaerobically showed a similar drop in viable counts for the first 48 h of incubation; however, at the lower levels of OxyraseTM, some cells survived, and resumed logarithmic growth at 96 h. To explore the effects of short term aerobic incubation in the presence of 0, 0.005, 0.05, and 0.5 Units OxyraseTM, cultures were examined microscopically after 4, 8, and 24 h. In the OxyraseTM‐containing broths, <90% of the cells exhibited rod shape morphology after 8 h, whereas in the untreated broth, most cells appeared coccoid. After 24 h, all cells exhibited coccoid morphology.

Antibacterial Activity of the Lactoperoxidase System Against Salmonella typhimurium in Trypticase Soy Broth in the Presence and Absence of a Heat Treatment

The antibacterial activity of the lactoperoxidase system (LP system) on the growth and survival of Salmonella typhimurium in tryptic soy broth (TSB) was determined. The LP system, consisting of lactoperoxidase (1 μg/ml), potassium thiocynante (KSCN) (5.9 mM) and H2O2 (2.5 mM), was found to have both bacteriostatic and bactericidal activities against strains of S. typhimurium. The bactericidal activity was clearly dependent on the initial inoculum level. Levels of 102 - 105 CFU/ml were killed at 37°C as opposed to the bacteriostatic activity with inoculum levels of 106 - 107 CFU/ml, which exhibited a 25-h lag. The LP system also enhanced thermal inactivation of S. typhimurium. D50°C-values were > 60 min (untreated broth) and 12 min (LP system activated); corresponding D52°c-values were 20 min and 7.5 min; corresponding D55°c-values were 14 min and 4 min; corresponding D60°C -values were 5 min and 2.5 min and corresponding Devalues were .31 min and .20 min.

Production of Thiol-dependent Haemolysins by Listeria monocytogenes and Related Species

Twenty-six strains belonging to the five main species of the genus Listeria were examined for production of thiol-dependent exotoxins. All strains of L. monocytogenes cultured in charcoal-treated broth secreted a haemolytic factor at a level ranging from 200 to 800 haemolytic units (HU) ml-1, except for the strain EGD (1500 HU ml-1) and the type strain CIP 82110T (10 HU ml-1). The haemolytic activity reached a maximum level by 8-10 h and then rapidly declined as soon as bacterial exponential growth ceased. The titres of haemolytic activity were markedly reduced when bacteria were grown in charcoal-untreated broth. The haemolytic factor produced by L. monocytogenes strains was characterized as listeriolysin O (Mr about 60,000), a member of the group of thiol-dependent exotoxins. Strains of Listeria ivanovii also produced high levels of thiol-dependent exotoxin (about 2500 HU ml-1), in both charcoal-treated and untreated broth. Small amounts of haemolytic factor (about 9-30 HU ml-1) were also produced by Listeria seeligeri in charcoal-treated broth. The haemolysin produced by L. seeligeri was identified for the first time as a thiol-dependent exotoxin of Mr about 60,000, antigenically related to listeriolysin O. As expected, we failed to detect thiol-dependent exotoxin in the two nonhaemolytic species, Listeria innocua and Listeria welshimeri.

Recovery of an Extracellular Alkaline Protease From Whole Fermentation Broth Using Reversed Micelles

AbstractThe liquid‐liquid extraction of an extracellular alkaline protease from its fermentation broth was carried out, using a reversed micellar organic solvent. Optimum process parameters were determined for extraction using a 250 mM AOT in isooctane micellar solution. With unequal phase volume ratios, purification factors as high as 6 have been obtained from completely untreated broth. Yields up to 56% were achieved from the same broth using a three‐stage cascade.

THE EFFECT OF ENVIRONMENTAL CONDITIONS ON THE VIABILITY AND GROWTH OF BACTERIA DAMAGED BY PHENOLS

SUMMARYThe effects of various environmental conditions on the viability and growth of normal Escherichia coli and Staphylococcus aureus cells, and of cells of these species which had been damaged by exposure to phenol, o‐cresol and p‐chloro‐m‐cresol, have been examined.With normal cells none of the conditions tried had any effect on the initial counts, but sometimes, more often with Staph. aureus, the bulk of growth eventually obtained in broth media was larger, especially when the medium had been made with pyridine extracted peptone, or when it had been treated with 0·1% of Norit charcoal or 0·02% of FeCl3.In contrast, damaged cells of both species were very sensitive to their environment. At room temperature, 0·1% of Norit added to tap water adsorbed more than 80% of the cells and the initial count was increased. Nevertheless the cells died thereafter. Damaged cells inoculated into broth also died, but when Norit was present both the rate and the extent of death were markedly reduced, though few cells were adsorbed. The addition of FeCl3 (0·02 or 0·03%) had no effect. At 37° damaged cells died faster than at room temperature, but the protective effect of Norit was still evident. In nephelometric studies of cultures growing in Norit treated broth the times to turbidity were shorter than those of control cultures in untreated broth, but broth treated with FeCl3 often gave longer times than the controls.In a comparison of broths prepared with peptone and/or Lab‐Lemco which had been extracted with pyridine to remove suspected toxic substances, the initial counts of treated cells were highest when only the peptone had been extracted. With media containing extracted Lab‐Lemco, or with both ingredients extracted, the counts were smaller but were still generally higher than in normal broth. The results of nephelometric studies were consonant with these findings: broths prepared with extracted ingredients generally gave shorter turbidity times than normal broth, especially with E. coli.The addition to broth of cations, especially Mg2+ (10–3 M), favoured the survival of damaged E. coli but did not influence that of Staph. aureus. But with both species, five times that concentration of Mg2+ was as effective as 0·1% of Norit, which was shown to adsorb lead, tin, copper, zinc, silver and cobalt from broth.Temperatures above 37° were unfavourable to the survival of damaged cells of both species, 44° often being completely inhibitory for Staph. aureus, but this effect was not due to traces of phenol in the inoculum. At 25° damaged E. coli recovered less well than at 30° and 37°, but damaged Staph. aureus did better at 25° and 30° than at 37°.

The Effect of Ricinoleated Vaccine of the Hemolytic Streptococcus (Scarlet Fever) on Animals

Abstract Of the many different substances which have been tried in detoxifying bacterial toxins for the purpose of immunization, sodium ricinoleate has recently been suggested as very suitable (1–6). Thus, it has also been reported that broth toxin from a culture of the hemolytic streptococcus (scarlet fever) when mixed with sodium ricinoleate and injected intramuscularly into man did not induce any severe reaction such as usually follows an administration of the same amount of untreated broth toxin; moreover, after the elapse of a certain time, the intracutaneous test became negative in a large percentage of cases. To gain some insight into the efficacy of soap-vaccine and into the mechanism of soap action, the following experiments have been carried out on mice. Method. Sodium ricinoleate was prepared from castor oil saponified by alcoholic potassium hydroxide and purified by cooling, by fractionation of its potassium, sodium, and barium salts by the method described in another paper which will be published later.