Yeast growth and biomass production are greatly influenced by the length of the
incubation period during cultivation. Therefore, this study was conducted to
investigate the growth kinetics of five Lipomyces starkeyi strains as determined by
biomass production. The five L. starkeyi strains, namely L. starkeyi ATCC 12659, L.
starkeyi MV-1, L. starkeyi MV-4, L. starkeyi MV-5 and L. starkeyi MV-8, were inoculated
in sterilized Yeast Malt broth, and, incubated for 192 hr at ambient temperature.
Biomass yields were assessed and calculated gravimetrically every 24 hr. Results
indicated that the optimal biomass production of L. starkeyi ATCC 12659, L. starkeyi
MV-1, L. starkeyi MV-4, L. starkeyi MV-5 and L. starkeyi MV-8 were at 120, 168, 144,
168 and 120 hr, with the concentrations of 6.64, 6.43, 9.78, 11.23 and 8.56 g/L,
respectively. These results indicate that each L. starkeyi strain requires specific
incubation period for the optimum production of fungal biomass. Therefore, by
cultivating each L. starkeyi strain at the predetermined incubation period, biomass
yields could significantly be improved for further downstream applications such as
single cell protein and lipid production.
Bioethanol is a very environmentally friendly liquid biofuel that is not only renewable, but also sustainable. It is currently
deemed as a highly suitable additive and substitute energy source to replace fossil based fuel. In this study, bioethanol
was produced from sago hampas by using commercial amylase, cellulase and Saccharomyces cerevisiae via sequential
saccharification and simultaneous fermentation (SSSF), a modified version of the simultaneous saccharification and
fermentation (SSF) process. SSSF was performed on sago hampas at 2.5 and 5.0% (w/v) feedstock load for five days. The
samples taken from the SSSF broths were analysed via high performance liquid chromatography (HPLC) for ethanol, glucose
and acetic acid production. From the results obtained, SSSF with 5.0% sago hampas loading exhibited the highest ethanol
production at 14.13 g/L (77.43% of theoretical ethanol yield), while SSSF using 2.5% sago hampas loading produced
ethanol at 6.45 g/L (69.24% of theoretical ethanol yield). This study has shown that ethanol not only can be produced
from sago hampas using different enzyme mixtures and S. cerevisiae via SSSF, but yields were also high, making this
process highly promising for the production of cheap and sustainable ethanol as fuel.