School of Engineering, University of Borås, SE-501 90 Borås, Sweden.
N Biotechnol. 2013 Jun 25;30(5):516-22. doi: 10.1016/j.nbt.2013.05.007. Epub 2013 May 25.
Pelleted growth provides many advantages for filamentous fungi, including decreased broth viscosity, improved aeration, stirring, and heat transfer. Thus, the factors influencing the probability of pellet formation of Rhizopus sp. in a defined medium was investigated using a multifactorial experimental design. Temperature, agitation intensity, Ca(2+)-concentration, pH, and solid cellulose particles, each had a significant effect on pelletization. Tween 80, spore concentration, and liquid volume were not found to have a significant effect. All of the effects were additive; no interactions were significant. The results were used to create a simple defined medium inducing pelletization, which was used for immobilization of a flocculating strain of Saccharomyces cerevisiae in the zygomycetes pellets. A flor-forming S. cerevisiae strain was also immobilized, while a non-flocculating strain colonized the pellets but was not immobilized. No adverse effects were detected as a result of the close proximity between the filamentous fungus and the yeast, which potentially allows for co-fermentation with S. cerevisiae immobilized in pellets of zygomycetes.
颗粒状生长为丝状真菌提供了许多优势，包括降低了发酵液的黏度，改善了通气、搅拌和传热效果。因此，采用多因素实验设计研究了在确定的培养基中影响根霉属微生物颗粒形成概率的因素。温度、搅拌强度、Ca(2+)-浓度、pH 值和固体纤维素颗粒对颗粒化都有显著影响。Tween 80、孢子浓度和液体体积没有发现有显著影响。所有影响都是累加的，没有显著的相互作用。这些结果被用来创建一个简单的确定的诱导颗粒化的培养基，该培养基用于固定絮凝酵母属酿酒酵母在接合菌颗粒中。还固定了一个形成花的酿酒酵母菌株，而不絮凝的菌株则殖民颗粒，但未被固定。由于丝状真菌和酵母之间的紧密接近，没有检测到任何不良影响，这可能允许与固定在接合菌颗粒中的酿酒酵母进行共发酵。
