Application of Lactobacillus johnsonii expressing phage endolysin for control of Clostridium perfringens.

Clostridium perfringens is frequently found in food and the environment and produces potent toxins that have a negative impact on both human and animal health and particularly on the poultry industry. Lactobacillus johnsonii FI9785, isolated from the chicken gastrointestinal tract, has been demonstrated to exclude Cl. perfringens in poultry. We have investigated the interaction of wild-type Lact. johnsonii FI9785 or an engineered strain expressing a cell wall-hydrolysing endolysin with Cl. perfringens in vitro, using a batch culture designed to simulate human gastrointestinal tract conditions. Co-culture experiments indicated that acid production by Lact. johnsonii is important in pathogen control. The co-culture of the endolysin-secreting Lact. johnsonii with Cl. perfringens showed that the engineered strain had the potential to control the pathogen, but the ability to reduce Cl. perfringens numbers was not consistent. Results obtained indicate that survival of high numbers of Lact. johnsonii will be essential for effective pathogen control. Significance and impact of the study: The bacterium Lactobacillus johnsonii FI9785 reduces numbers of the pathogen Clostridium perfringens in vitro. Biocontrol was improved by engineering the strain to produce and export a cell wall-hydrolysing endolysin, but good survival of the producer strain is essential. The production of bacteriophage endolysins by commensal bacteria has the potential to improve competitive exclusion of pathogens in the gastrointestinal tract.

Does the light influence astaxanthin production in Xanthophyllomyces dendrorhous?

Astaxanthin (C40H52O4) is an important natural pigment that has considerable promising applications in human health. Until now, many efforts were made aimed to develop economically sustainable bioprocesses alternative to the chemical synthesis, to satisfy the increasing demand of this ketocarotenoid from feed, food and cosmetic industries. The extraction of natural astaxanthin from the yeast Xanthophyllomyces dendrorhous till now seems to be rather expensive if compared with chemically synthesized astaxanthin. In this article, astaxanthin production by Xanthophyllomyces dendrorhous under two different conditions was studied: a first effort was made using a conventional reactor while a second using an enlightened one. This research was aimed also to optimise astaxanthin production by testing the influence of the light and of some nutrient sources. From fermentation tests, an astaxanthin yield ranging about 970 µg g(-1) was obtained after fed batch cultivation in the conventional reactor. In the enlightened reactor lower values, about 930 µg g(-1), were found.

Production of feruloyl esterases and xylanases by Talaromyces stipitatus and Humicola grisea var. thermoidea on industrial food processing by-products.

Feruloyl esterase (FAE) and xylanase activities were detected in culture supernatants from Humicola grisea var. thermoidea and Talaromyces stipitatus grown on brewers' spent grain (BSG) and wheat bran (WB), two agro-industrial by-products. Maximum activities were detected from cultures of H. grisea grown at 150 rpm, with 16.9 U/ml and 9.1 U/ml of xylanase activity on BSG and WB, respectively. Maximum FAE activity was 0.47 U/ml and 0.33 U/ml on BSG and WB, respectively. Analysis of residual cell wall material after microbial growth shows the preferential solubilisation of arabinoxylan and cellulose, two main polysaccharides present in BSG and WB. The production of low-cost cell-wall-deconstructing enzymes on agro-industrial by-products could lead to the production of low-cost enzymes for use in the valorisation of food processing wastes.

Synergy between xylanases from glycoside hydrolase family 10 and family 11 and a feruloyl esterase in the release of phenolic acids from cereal arabinoxylan.

The bioconversion of waste residues (by-products) from cereal processing industries requires the cooperation of enzymes able to degrade xylanolytic and cellulosic material. The type A feruloyl esterase from Aspergillus niger, AnFaeA, works synergistically with (1-->4)-beta-D-xylopyranosidases (xylanases) to release monomeric and dimeric ferulic acid (FA) from cereal cell wall-derived material. The esterase was more effective with a family 11 xylanase from Trichoderma viride in releasing FA and with a family 10 xylanase from Thermoascus aurantiacus in releasing the 5,5' form of diferulic acid from arabinoxylan (AX) derived from brewers' spent grain. The converse was found for the release of the phenolic acids from wheat bran-derived AXs. This may be indicative of compositional differences in AXs in cereals.

SCP and crude pectinase production by slurry-state fermentation of lemon pulps.

Single cell protein (SCP) and crude pectinolytic enzymes production from citrus pulps is reported. SCP and enzymes were produced by slurry-state flask cultivation of Aspergillus niger and Trichoderma viride on pulps from lemon juice clarification. Production as well as crude pectinase activity was not affected by the high dry matter content of the pulps. Both the protein content in the residue and the enzyme activity in the supernatant were higher in T. viride than in A. niger culture. The crude pectinase of T. viride, whose specific activity was similar to that found for a commercial concentrated preparation, could be utilized in the same citrus processing factory as well as in other factories which use large amounts of pectinolytic crude preparations, for example to enhance depuration plant performance.

Yeast production from virgin grape marc.

An alternative utilization of virgin grape marc (VGM) to produce SCP from S. ceretisiae is reported. A simple extraction method of fresh grape marc produces a sugar-rich solution: through fed-batch fermentation, a high-value yeast biomass instead of a low-value product like ethanol can be produced. Productivity and quality of yeast are similar to these obtainable from molasses. The convenience of yeast production from VGM is briefly discussed; it appears of great interest in south Italy and generally in grape-producing countries, specially if these lack relevant sources of fermentable sugars.

Biological effects of hesperidin, a Citrus flavonoid. (note II): hypolipidemic activity on experimental hypercholesterolemia in rat.

Hesperidin, the most important flavanone of Citrus sp., significantly increases HDL and lowers cholesterol, LDL, total lipid and triglyceride plasma levels in normolipidemic rats and in rats with diet- and triton-induced hyperlipidemia.

[A case of sepsis of the urinary tract caused by Candida albicans]. / Un caso di sepsi delle vie urinarie sostenuto da "Candida albicans"

The AA. describe a case of secondary sepsis of the urinary tract by Candida albicans. The subject, after an operation of right inguinal herniotomy, was treated prophylactically with Ceporin. Three days after the operation he was catheterized and Bactrin was added to Ceporin. It was possible to isolate from urine a strain of Candida. Morphological, cultural, biochemical features, as well as fermentation and assimilation tests, and the biological assay of pathogenicity on the rabbit, allowed the strain of the yeast to be identified as Candida albicans. Moreover, an extract obtained from the yeast, tested by Wadsworth's micromethod against the serum of the patient, showed two lines of precipitation. The patient recovered after treatment with antimycotics.