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Table 5 Energy balance of the fungal lipid production on anaerobic digestate

From: Fungal fermentation on anaerobic digestate for lipid-based biofuel production

Energy balancea AD Hydrolysis/detoxificationb Fungal fermentationc
Energy input (MJ/1000 kg dry mixed feed) −1971.96d −1593.48e −9048.27f
Energy output (MJ/1000 kg dry mixed feed) 8450.00g 3830.80h 344.00i
Net energy (MJ/1000 kg dry mixed feed) 6478.04 2237.32 −8704.27
Overall net energy (MJ/1000 kg dry mixed feed) 11.09
  1. All inputs are assigned “−”, and all outputs are assigned “+”. The system includes AD, hydrolysis/detoxification, and fungal fermentation (Fig. 5)
  2. aData were calculated and adjusted based on 1000 kg dry mixed feed
  3. bHydrolysis/detoxification includes unit operations of pretreatment, enzymatic hydrolysis, and detoxification
  4. cThe fungal fermentation includes unit operations of fungal fermentation and biomass drying
  5. dThe energy input for the AD unit includes both heat and electricity, which is calculated from the data in Table 1
  6. eCompared to the pretreatment and enzymatic hydrolysis, the energy demand for the detoxification (under 50 °C and 5 h) is negligible. Thus, the energy consumption of 262 MJ/m3 reaction solution for the pretreatment and enzymatic hydrolysis was used for the calculation [25]. The energy input of the hydrolysis/detoxification is 1593.48 MJ/1000 kg dry mixed feed
  7. fThe energy input of the fungal fermentation operation is 10,286.67 MJ/1000 kg dry mixed feed according to the reference numbers of 1938.77 MJ/m3 fermentation broth and 1.99 MJ/kg wet biomass [25]. The amount of the fermentation broth is 4511 kg. The amount of the wet fungal biomass is 152 kg
  8. gThe energy output of the AD is the methane energy. Low heating value of methane of 50 MJ/kg methane was used for the calculation
  9. hThe lignin has a low heating value of 24.4 MJ/kg lignin. 157 kg lignin/1000 kg mixed feed was generated from the process
  10. iThe lipid as the product is used for biodiesel production. The lipid has a low heating value of 40.0 MJ/kg lipid