Glycerol/Glucose Co-Fermentation: One More Proficient Process to Produce Propionic Acid by Propionibacterium acidipropionici

Cosubstrates fermentation is such an effective strategy for increasing subject metabolic products that it could be available and studied in propionic acid production, using glycerol and glucose as carbon resources. The effects of glycerol, glucose, and their mixtures on the propionic acid production by Propionibacterium acidipropionici CGMCC1.2225 (ATCC4965) were studied, with the aim of improving the efficiency of propionic acid production. The propionic acid yield from substrate was improved from 0.475 and 0.303 g g−1 with glycerol and glucose alone, respectively, to 0.572 g g−1 with co-fermentation of a glycerol/glucose mixture of 4/1 (mol/mol). The maximal propionic acid and substrate conversion rate were 21.9 g l−1 and 57.2% (w/w), respectively, both significantly higher than for a sole carbon source. Under optimized conditions of fed-batch fermentation, the maximal propionic acid yield and substrate conversion efficiency were 29.2 g l−1 and 54.4% (w/w), respectively. These results showed that glycerol/glucose co-fermentation could serve as an excellent alternative to conventional propionic acid fermentation

Bio-produced Propionic Acid: A Review

Propionic acid is a platform chemical, antifungal agent and important chemical intermediate. Current industrial production of propionic acid is mainly through petrochemical processes because the conventional method of the propionic acid fermentation is uneconomical due to low product yield, productivity and product concentration caused by end-product inhibition. The coproduction of acetic and succinic acids in the propionic acid fermentation processes also makes downstream processing more complicated and costly. To the best of our knowledge there are several and recent reviews in the available literature on propionic acid fermentation processes and strain improvement techniques, but only a few on product recovery and purification, i.e. downstreaming. However, to realize a biorefinery, where propionic acid is a key intermediate, complex discussion of up-, and downstreaming is required. Therefore in this review a short overview of the whole bio-based propionic acid production process is presented including recent results of both upstream and downstream area. Thus the biosynthetic pathways, the significant results of native and recombinant producer strains as well as product recovery are discussed

Laboratory and field evaluation of acetic acid-based lures for male Asian citrus psyllid, Diaphorina citri.

The Asian citrus psyllid (ACP) is a vector of a pathogen associated with greening and thus a major problem in citriculture worldwide. Lures are much needed for improving ACP trapping systems for monitoring populations and surveillance. Previously, we have identified acetic acid as a putative sex pheromone and measured formic acid- and propionic acid-elicited robust electroantennographic responses. We have now thoroughly examined in indoor behavioral assays (4-way olfactometer) and field tests the feasibility of these three semiochemicals as potential lures for trapping ACP. Formic acid, acetic acid, and propionic acid at appropriate doses are male-specific attractants and suitable lures for ACP traps, but they do not act synergistically. An acetic acid-based homemade lure, prepared by impregnating the attractant in a polymer, was active for a day. A newly developed slow-release formulation had equal performance but lasted longer, thus leading to an important improvement in ACP trap capture at low population densities

Bacteriology of cheese IV. Factors affecting the ripening of Swiss-type cheese made from Pasteurized milk

Propionic acid bacteria were found in various cheeses, including Iowa swiss-type, domestic swiss and cheddar. Swiss-type cheese with a desirable sweet flavor generally contained relatively large numbers of propionic acid bacteria, and cheese with a poor flavor generally contained few or none (in 0.1 gram). All the domestic swiss cheese contained rather large numbers of propionic acid bacteria. About 85 percent of the cheddar cheese, of both good and poor quality, contained propionic acid bacteria; there was no correlation between the numbers of the organisms and the quality. A canned cheddar cheese which had eyes similar to those in swiss cheese contained a considerable number of propionic acid bacteria. Eighteen strains of propionic acid organisms were used in the manufacture of swiss-type cheese from pasteurized milk. Several of the cultures were rather consistent in the type of flavor produced, while others were variable. Results indicated that certain cultures rather regularly produced cheese having either an excellent or good flavor. The addition of propionic acid organisms was not beneficial from the standpoint of eye formation, since none of the cultures were consistent in producing good eyes. In several instances, the four cheese in a series showed the same type of eye formation, even though one of the cheese was a control, while the other three were made with propionic acid cultures. Cheese in which no propionic acid bacteria could be detected in 0.1 gram sometimes developed satisfactory eyes

Black Soldier Fly (Hermetia illucens) Prepupa Phase Fermentation by Organic Acids to Decrease Chitin Content

Black Soldier Fly has high protein but there are anti-nutrients, namely the presence of chitin content that cannot be digested by livestock such as poultry and monogastrics. Chitin is a natural polysaccharide that is abundantly found from crustacean organisms and insects. Chitin is usually bound to the shell or exoskeleton, proteins, minerals and pigments. Black Soldier Fly in the prepupa phase has high protein, dark brown body and a rather hard exoskeleton which causes a high chitin content. The aim of this research was to determine the concentration of propionic and formic acids which could reduce the chitin content of the prepupa phase of the Black Soldier Fly (Hermetia illucens) fermentation. This study used a completely randomized design (CRD) with five treatments, namely P1 = (BSF added 50% propionic acid + 50% formic acid), P2 = (BSF added 80% propionic acid and formic acid + 20% aquadest), P3 = (BSF added 60% propionic and formic acids + 40% aquadest), P4 = (BSF added 40% propionic and formic acids + 60% aquadest), P5 = (BSF added 20% propionic acid and formic acid + 80% aquadest) with three repetitions. The results of this study indicate that the P1 treatment (addition of 50% propionic acid + 50% formic acid) resulted in the lowest reduction in chitin content, namely (11.00%), pH value (4.7), total titrated acid (0.014%) and organoleptic (light brown color, very sour aroma and harsh texture)

THE EFFECT OF PROPIONIC ACID ADDITION IN POULTRY DIETS ON THE INTERNAL ORGANS OF BROILER CHICKENS

This study aims to determine the effects of adding propionic acid in the poultry diets on the internal organs of broiler chickens. The livestock used were 180 broilers with Cobb strain. This study used a completely randomized design (CRD) consisting of 3 treatments and 6 replications.The treatments in this study consisted of: P0= commercial feed without propionic acid addition; P1= commercial feed with addition of 0.5%propionic acid; and P2= commercial feed with 0.75% propionic acid. The parameters observed included live weight, spleen percentage, gizzardpercentage, liver percentage, and small intestine length. The results showed that the addition of propionic acid in the broiler feed had a significant effect (P0.05) on the live weight and had no significant effect (P0.05) on the percentage of spleen, percentage of gizzard, percentage of liver, and small intestine length. The conclusion of this study was that the addition of propionic acid in poultry feed at a dose of 0.75% did not negatively affect the internal organs and the length of the small intestine of broiler chickens

Preservative Effects of Covering and Propionic Acid on Alfalfa Haylage in Bunker Silos

The preservation efficiency of covering alfalfa haylage with black plastic (polyethylene) and/or treating haylage with propionic acid was studied in two trials. Experiment 1 was designed to evaluate the influence of both covering and treatment with propionic acid on haylage chemical composition and heifer growth. In experiment 1, prop ionic acid was administered to the haylage at the chopper at 0.02% of the fresh forage weight. Chemical composition and ensiling temperature of the haylage were monitored and animal growth was measured with 16 Holstein heifers. Covered haylage was superior to treated haylage in quality as measured by chemical analyses and animal performance. Propionic acid lowered ensiling temperature to a lesser extent than covering. Experiment 2 was designed to compare a control alfalfa haylage (covered/untreated) to an uncovered haylage topically treated with 100% propionic acid. Ensiling temperature, chemical content, and animal performance of dairy heifers were evaluated. The control haylage had lower ensiling temperature and was superior in quality as measured by chemical analyses and heifer performance. Propionic acid addition was ineffective in lowering ensiling temperature and limiting extended fermentation. The data suggests that covering was more efficient than propionic acid addition in preserving alfalfa haylage in bunker silos

Use of Natural Antimicrobials to Control Spoilage in Marinara-Type Sauce

Marinara-type sauces were created using three natural antimicrobials, as well as two combination treatments (natamycin, propionic acid, cultured dextrose, natamycin-propionic acid, and natamycin-cultured dextrose) and two controls (sodium benzoate-potassium sorbate, no preservatives). Samples were subjected to a shelf-life study at 20 C with both non-inoculated sauce and sauces that were either inoculated with Zygosaccharomyces bailii or a cocktail of thermophilic fermentative organisms. Natamycin and Natamycin-propionic acid treatments had fewer log colony counts (CFU/g) of yeast and lactic acid bacteria than the negative control after 42 days of storage and performed as well or better than the positive control throughout the storage period. No sensory differences were detected (P\u3e0.05) between the natamycin treatment when compared to the industry standard (positive control), but the natamycin-propionic acid treatment was different (P\u3c0.05). Results indicate that natamycin and/or natamycin-propionic acid could be used as a natural alternative in the formulation of marinara sauce

Effect of propionic acid on Campylobacter jejuni attached to chicken skin during refrigerated storage

The ability of propionic acid to reduce Campylobacter jejuni on chicken legs was evaluated. Chicken legs were inoculated with Campylobacter jejuni. After dipping legs in either water (control), 1% or 2% propionic acid solution (vol/vol), they were stored at 4ºC for 8 days. Changes in C. jejuni, psychrotrophs and Pseudomonas counts were evaluated. Washing in 2% propionic acid significantly reduced (P < 0.05) C. jejuni counts compared to control legs, with a decrease of about 1.62 log units after treatment. Treatment of chicken legs with 1 or 2% propionic acid significantly reduced (P < 0.05) numbers of psychrotrophs 1.01 and 1.08 log units and Pseudomonas counts 0.75 and 0.96 log units, respectively, compared to control legs. The reduction in psychrotrophs and Pseudomonas increased throughout storage. The highest reductions obtained for psychrotrophs and Pseudomonas counts in treated legs were reached at the end of storage, day 8, being 3.3 and 2.93 log units, respectively, compared to control legs. Propionic acid treatment was effective in reducing psychrotrophs and Pseudomonas counts on chicken legs throughout storage. It is concluded that propionic acid is effective for reducing C. jejuni populations in chicken. [Int Microbiol 18(3):171-175 (2015)]Keywords: Campylobacter jejuni · Pseudomonas spp. · poultry · meat safety · pathogen reductio