Robert P. Tengerdy

Mixed culture solid substrate fermentation of Trichoderma reesei with Aspergillus niger on sugar cane bagasse

Abstract Trichoderma reesei LM-UC4, the parent strain, and its hypercellulolytic mutant LM-UC4E1 were co-cultured with Aspergillus niger ATCC 10864 in solid substrate fermentation on alkali-treated sugar cane for cellulolytic enzyme production. Bagasse was supplemented with either soymeal or with ammonium sulfate and urea, and fermented at 80% moisture content and 30°C. Mixed culturing produced better results with the inorganic supplement. The mutant strain was more responsive to mixed culturing than the parent strain when A. niger was the cooperating partner. In a mixed culture of the mutant with inorganic N-source, 10% more biomass, but 63% more cellulase, 85% more endoglucanase and 147% more β-glucosidase was produced than in single culture. Since co-culturing helped enzyme production more than growth, it appeared that synergistic interactions not directly related to growth were responsible for increased enzyme production. Although soymeal supplementation increased biomass production in the same mixed culture by 30%, it did not increase enzyme production. Mixed culturing is thus beneficial for the economic production of cellulases on nutritionally poor agricultural residues, without the need for supplementation with expensive organic supplements.

Production of cellulase on sugar cane bagasse by fungal mixed culture solid substrate fermentation

Trichoderma reesei LM-UC4 and its mutant LM-UC4E1 were co-cultured with Aspergillus phoenicis QM329 for cellu-lase production on bagasse by mixed culture solid substrate fermentation. A mutual synergism was observed between the parent Trichoderma strain and the Aspergillus, resulting in enhanced combined biomass production and corresponding increased in cellulase, endoglucanase and b-glucosidase activities. Such synergism was absent with the mutant Trichoderma strain suggesting that in the hypermutation the ability for cooperative interaction with other microbes was lost.

Production of phytase by Mucor racemosus in solid-state fermentation.

Phytase production was studied by three Mucor and eight Rhizopus strains by solid‐state fermentation (SSF) on three commonly used natural feed ingredients (canola meal, coconut oil cake, wheat bran). Mucor racemosusNRRL 1994 (ATCC 46129) gave the highest yield (14.5 IU/g dry matter phytase activity) on coconut oil cake. Optimizing the supplementation of coconut oil cake with glucose, casein and (NH4)2SO4, phytase production in solid‐state fermentation was increased to 26 IU/g dry matter (DM). Optimization was carried out by Plackett‐Burman and central composite experimental designs. Using the optimized medium phytase, α‐amylase and lipase production of Mucor racemosusNRRL 1994 was compared in solid‐state fermentation and in shake flask (SF) fermentation. SSF yielded higher phytase activity than did SF based on mass of initial substrate. Because this particular isolate is a food‐grade fungus that has been used for sufu fermentation in China, the whole SSF material (crude enzyme, in situ enzyme) may be used directly in animal feed rations with enhanced cost efficiency.

Production of lovastatin by a wild strain of Aspergillus terreus

Of 68 Aspergillus terreus, three produced lovastatin with equivalent or better yield than strain ATCC 20542 originally described for lovastatin production. Medium optimization experiments with the best isolate (TUB F-514) indicated that lactose, rapeseed meal and KNO3 were the best carbon, organic nitrogen and inorganic nitrogen sources, respectively. In shake-flasks with optimized medium containing 4 % (w/v) lactose, 400 μg lovastatin/ml was produced, with a yield of 10 mg/g lactose. In solid substrate fermentation on extracted sweet sorghum pulp supplemented with cheese whey 1500 μg lovastatin/g dry weight was produced with a yield of 37.5 mg/g lactose.

Mixed culture solid substrate fermentation for cellulolytic enzyme production

SummaryCellulolytic and hemicellulolytic enzymes were produced on extracted sweet sorghum silage by mixed culture solid substrate fermentation with Trichoderma reesei LM-1 (a Peruvian mutant) and Aspergillus niger ATCC 10864. Optimal cellulose and xylanase levels of 4 IU/g dry weight (DW) and 180 IU/g DW, respectively, were achieved in 120 h-fermentation when T. reesei, inoculated at 0 h, was followed by the inoculation of A. niger at 48 h.

The role of vitamin E in immune response and disease resistance

Vitamin E supplementation enhances humoral and cell-mediated immunity, and augments the efficiency of phagocytosis in laboratory animals, farm animals, and humans. In its disease protection effect vitamin E interacts with other antioxidant nutrients and with other nutrients in the diet. Other antioxidant nutrients, such as vitamin A and beta carotene, also enhance disease resistance. Beta carotene is effective in combination with vitamin E. The optimal dose of vitamin E for maximum protection depends on many factors; thus it has to be established case by case. The delivery system of vitamin E greatly influences its effectiveness. A targeted delivery to localized immunocompetent cells in adjuvant formulations is far more effective than a general dispersed delivery in a diet. Vitamin E adjuvants provided greater immunoprotection against enterotoxemia and epididymitis in sheep than conventional vaccines.

Vitamin E, immune response, and disease resistance.

Vitamin E as a dietary supplement or as part of an adjuvant vaccine formulation increases humoral and cell-mediated immunity and disease resistance in laboratory animals, farm animals, and humans. Adjuvant administration has far greater effect than dietary supplementation. Vitamin E as an antioxidant protects the cells of the immune response from peroxidative damage; possibly through a modulation of lipoxygenation of arachidonic acid, vitamin E alters cell membrane functions and cell-cell interactions. The most pronounced effect of vitamin E is on immune phagocytosis. Dietary supplementation is beneficial to animals, especially under stress, in decreasing susceptibility to infections. Vitamin E adjuvant vaccines have provided greater immunoprotection against enterotoxemia and epididymitis in sheep than conventional vaccines.

Xylanase production by fungal mixed culture solid substrate fermentation on sugar cane bagasse

Trichoderma reesei was co-cultured with either Aspergillus niger or A. phoenicis in solid substrate fermentation on sugar cane bagasse for xylanase production. When soymeal was used as nitrogen supplement, optimal activities of cellulase (14-15 IU/g dry wt) and xylanase (2,600-2,800 IU/g dry wt) were attained by both mixed culture systems in 72 h of fermentation, corresponding to xylanase volumetric productivities of 5,500-5,900 lU/L.h.

Protection of Chicks Against E. coli Infection by Dietary Supplementation with Vitamin E

Summary Dietary supplementation of 150–300 mg vitamin E (dl-α-tocopheryl acetate)/kg gave increased protection against a relatively moderate (25–30% mortality) E. coli infection. A correlative 2-3-fold increase in log2 antibody titer against the E. coli indicates that increased chick survival was in part immunologic. We thank Hoffmann La Roche, Inc., for supplying the vitamin E and for the vitamin E assays of the diets.

Vitamin E, Immunity and Disease Resistance

The effect of vitamin E on immune responses and disease resistance is now well established and has been covered in recent reviews (Axelrod, 1978; Nockels, 1978; Sheffy and Schultz, 1979; Tengerdy, 1978). Predictably, vitamin E ([dl])-α-tocopheryl-acetate) deficiency leads to impaired immune response and disease protection (Axelrod, 1978). Large doses of vitamin E, much larger than the presently accepted recommended minimal daily allowance, on the other hand, enhance certain immune responses and can lead to increased disease resistance in a number of animal species against a variety of infectious agents. Table I. illustrates this point.