Production of Microbial Lipids from Rice Straw Hydrolysates by Lipomyces starkeyi for Biodiesel Synthesis

Abstract

To minimize the cost of biodiesel production, massively available biomass, rice straw was selected as starting material for fermentation by oleaginous yeast, Lipomyces starkeyi. Acid hydrolysis was carried out to obtain Rice Straw Hydrolysates (RSH). Maximum amount of glucose was liberated with 3.5% H 2 SO 4. Highest levels of biomass (~12 g/L) and lipid content (~36%) of L. starkeyi were obtained through fermentation of RSH produced with 3.5% H 2 SO 4. The optimum pH for biomass yield and lipid accumulation of L. starkeyi was 6.0. Periodic supplementation of fresh RSH increased lipid content and lipid yield approximately15% and 40%, respectively. The growth and lipid accumulation of L. starkeyi were enhanced when carbon and nitrogen sources were supplemented with RSH. Gas chromatographic analysis revealed that the lipid obtained from L. starkeyi cultivated with RSH was composed of saturated and unsaturated fatty acids. The fatty acid composition of this microbial lipid is similar to that of vegetable oils. The results reported herein indicate that rice straw might be a valuable alternative feedstock for microbial lipids production by L. starkeyi for biodiesel synthesis.

Lipid production and heavy metals adsorption by an Aspergillus fumigatus GAH1 isolate

“…On the basis of these results, peptone was designated as the best nitrogen source for both lipid accumulation and biomass production. Similarly, it has been reported that peptone as an organic nitrogen source enhanced biomass and oil production by Tolyposporium ehrenbergii, Sphacelotheca reiliana, Lipomyces starkeyi, and Tricosporon fermentans (Farag et al, 1983;Zhu et al, 2008;Azad et al, 2014). Inorganic nitrogen sources such as ammonium nitrate and potassium nitrate were found to be favorable for lipid accumulation during the cultivation of Cunninghamella japonica and Aspergillus versicolor, respectively (Lunin et al, 2013;Karatay and Doenmez, 2014).…”

Rice waste streams as a promising source of biofuels: feedstocks, biotechnologies and future perspectives

“…Azad et al [78] optimized pH values of a fermentation broth containing H2SO4-hydrolysated RS as a carbon source for Lipomyces starkeyi, and found that the yeast accumulated microbial lipids up to 36.14% of cell dry weight (CDW). Diwan et al [150] developed an effective H2SO4 based mild saccharification of RS and successfully employed the crude, non-detoxified hydrolysate for growth of the yeast Mortierella alpina MTCC-6344 that accumulated lipids up to 40% of CDW.…”

Simultaneous Reclamation of Sago Starch Processing Effluent Water and <i>Rhizopus oligosporus</i> Cultivation at Different pH Conditions

“…The growth and biomass production of fungi vary when cultured under different cultivation conditions [23,24]. These conditions are generally affected by several parameters, including pH [18,25]. The biomass production by R. oligosporus in sago effluent under different initial pH is presented in Fig.…”