Pichia pastoris is able to utilize methanol as its sole carbon and energy source, exists mainly as a haploid during the asexual growth period.
Microorganism Strain Culture
Strain culture is the process of cultivating, propagating and maintaining microbial strains in vitro. This technique is commonly used in microbiological research, industrial fermentation, and biologics production. Culture conditions need to consider the physiological characteristics of microorganisms, including temperature, gas composition, nutrients, etc. The stability and vitality of strains can be maintained through regular passage and culture. Strain culture is widely used in life science research, food industry, medicine and environmental science and other fields, providing a basis for experiments in microbiology and related fields.
Related Experimental Schemes
Anaerobic bacterial culture detects viable bacteria that can grow under oxygen-depleted conditions; the readout is visible colony formation or broth turbidity after incubation in a chamber, jar, pouch, bag, or roll-tube system that maintains anaerobiosis. Oxygen control is central to the method because recovery depends on limiting oxygen exposure during collection, transport, inoculation, and incubation.
The protocol is based on established methods for cultivating Saccharomyces cerevisiae in planktonic (free-floating) culture, focusing on growth kinetics, high-throughput phenotyping, and quantitative assessment of cellular responses. Key principles include the use of defined media for controlled growth conditions, monitoring of optical density (OD) over time to assess exponential growth phases, and application of microplate reader-based assays for sensitive and scalable measurements of yeast growth and chemical sensitivity.
Aerobic bacterial batch culture grows a closed inoculated population in broth or on agar without continuous medium replacement; growth readouts include turbidity/OD for total suspended biomass and colony-forming units for viable cells able to form colonies on agar. OD-based growth curves reflect light scattering by cells, but OD is instrument-, pathlength-, species-, cell-size-, and density-dependent, so OD should be calibrated or interpreted alongside viable counts when quantitative cell density is required.
Microaerophilic/capnophilic bacterial culture detects viable bacteria that grow only or optimally under reduced oxygen and/or elevated carbon dioxide, with the readout generated by visible colony recovery, colony density, or growth in liquid culture; thermophilic Campylobacter grew under 5-10% O2 with 1-10% CO2, while Helicobacter pylori culture studies describe growth under 5-19% O2 and 5-10% CO2, with CO2 being required for H. pylori and contributing to C. jejuni capnophilic growth through bicarbonate-linked metabolism.
Selective and differential bacterial isolation culture separates viable bacteria by plating specimens on solid media that both suppress unwanted organisms and display interpretable colony phenotypes. MacConkey-type media use bile salts to support intestinal Gram-negative organisms while distinguishing lactose-fermenting bacteria in fecal material; sorbitol-MacConkey replaces lactose with sorbitol to detect non-sorbitol-fermenting Escherichia coli O157:H7; mannitol salt agar selectively recovers Staphylococcus aureus and differentiates yellow mannitol-positive colonies; chromogenic orientation media use enzyme-substrate color reactions to presumptively distinguish uropathogens on primary plates.
Filamentous fungal mold culture and sporulation assays grow hyphae under defined nutritional and environmental conditions until asexual spores, commonly conidia, are produced; the main readouts are colony growth, sporulation onset, conidial yield, conidial morphology, viability, and, when relevant, downstream infectivity or stress phenotype.
Bacterial-fungal co-culture assays measure interkingdom biofilm formation, physical association, viable cell recovery, biomass accumulation, metabolic activity, and species-specific interaction outcomes. In classic Candida albicans-Staphylococcus aureus models, S. aureus preferentially associates with C. albicans hyphae, mixed biofilms can increase bacterial recovery compared with bacterial monoculture, and readouts include CFU counting, microscopy, crystal violet biomass staining, and XTT metabolic activity. For C. albicans-Pseudomonas aeruginosa co-culture, the assay can also detect antagonistic or matrix-associated interactions, including phenazine-associated fungal toxicity on solid medium and increased dual-species biofilm biovolume or thickness in some biofilm conditions.
Fungal biofilm culture is an in vitro method for growing surface-attached fungal communities, most commonly Candida albicans, on abiotic substrates such as polystyrene wells, silicone elastomer, or polymethylmethacrylate; the assay models adhesion, proliferation, filamentation, extracellular-matrix-associated maturation, and dispersion. Biofilm output can be read by optical density at 600 nm for adherent biomass, XTT reduction for metabolic activity, CFU recovery for viable attached or dispersed cells, and microscopy for architecture.
