Materials and methods

The strain used was Pichia sp. (strain #2) obtained from Cambrium (Berlin, Germany). A microbial suspension was prepared by growing Pichia sp. strain in tubes containing 10 mL of YPD (glucose) broth overnight at 27 °C for 24 h. Growth kinetics were studied using a YPD (glycerol version) (YPD - G), basal salts fermentation media prepared with glucose (Basal salts - S) and glycerol (Basal salts - G), citric acid prepared with glucose (Citric acid - S) and glycerol (Citric acid - G), one per each treatment. Sterile 96-well flat-bottomed plates were filled with 250 µL per well. YPD (glucose version) was used as positive control YPD - S. The microbial suspension was diluted to an initial absorbance of 0.05 at 600 nm (OD600). Growth kinetics were determined by monitoring OD600 at 27 °C for 21 h in a microplate reader (Biotek, Winooski, VT, USA).

Data <- readxl::read_xlsx("/Users/jessmontzam/Library/CloudStorage/OneDrive-Personal/Laboral/CENIBiot/Proyectos/2022/2022 Cambrium/20220129 Pichia preliminary results.xlsx", sheet = "R") 
Filtro <- c("YPD - S", "YPD - G", "Basal salts - S", "Basal salts - G", "Citric acid - S", "Citric acid - G")

DataFiltrada <- Data %>%
    filter(Sample %in% Filtro)

DataFiltrada$Sample <- factor(DataFiltrada$Sample, levels = Filtro)

Overlay <- ggplot(DataFiltrada, aes(x = Time, y = OD600, color = Sample)) +
  geom_point(size = 2.5) +
  geom_errorbar(alpha = 0.5, aes(ymin = OD600 - Error, ymax = OD600 + Error)) +
  labs(x = "Time (h)", color = "Sample")

Overlay 

Fwrap <- ggplot(DataFiltrada, aes(x = Time, y = OD600, color = Sample)) +
  geom_point(size = 2.5) +
  geom_errorbar(alpha = 0.5, aes(ymin = OD600 - Error, ymax = OD600 + Error)) +
  labs(x = "Time (h)", color = "Sample") +
  facet_wrap(~Sample)

Fwrap

Conclusion

According to the results shown, YPD and citric acid media are selected for optimization of the culture medium.