Consolidated bioprocesses for efficient bioconversion of palm biomass wastes into biodiesel feedstocks by oleaginous fungi and yeasts.

• Lignocellulolytic oleaginous fungi could pretreat biomass wastes and produce lipid. • Simultaneous saccharification and fermentation (SSF) was efficient process. • Non-sterile fed-batch SSF is practical and effective for yeast lipid production. • Combination use of both oleaginous fungi and yeast increased overall lipid yield. • Consolidated bioprocess of enzyme and lipid production was feasible. Consolidated bioprocesses for bioconversion of lignocellulosic biomass into biodiesel feedstocks were developed. Palm empty fruit bunch (EFB) was biologically pretreated coupling with fungal lipid production (121.4 ± 2.7 mg/g-EFB) by lignocellulolytic oleaginous fungi prior to lipid production by oleaginous yeasts. In subsequent separate hydrolysis and fermentation (SHF) of fungal pretreated EFB (FPEFB), the oleaginous yeast with the maximum lipid yield of 37.0 ± 0.1 mg/g-FPEFB was screened. While a higher lipid yield of 47.9 ± 1.5 mg/g-FPEFB was achieved in simultaneous saccharification and fermentation (SSF) with less enzyme requirement. Fed-batch SSF of non-sterile FPEFB was proven as a practical and efficient strategy to increase lipid yield up to 53.4 ± 0.5 mg/g-FPEFB. Total lipid yield by both fungi and yeast was 165.0 ± 4.4 mg/g-EFB. Interestingly, the consolidated bioprocesses of enzyme and lipid production also achieved comparable total lipid yield of 149.3 ± 6.6 mg/g-EFB. These strategies may contribute greatly to cost-effective and sustainable bioconversion of lignocellulosic biomass into biodiesel feedstocks. [ABSTRACT FROM AUTHOR]