Richard Lab:SSCF: Difference between revisions
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##1g trisodium citrate dihydrate | ##1g trisodium citrate dihydrate | ||
##0.33g citric acid monohydrate | ##0.33g citric acid monohydrate | ||
#Chaekc that the pH is around 5.5 | |||
#Autoclave the medium | #Autoclave the medium | ||
#After autoclaving and cooling add the following: | #After autoclaving and cooling add the following: |
Revision as of 11:19, 14 September 2011
Introduction
This protocol is for the quantitative simultaneus saccharification and co-fermentation of ensiled ligno-cellulosic biomass using Zymomonas mobilis 8b. The amounts given in this protocol are for fermenting one biomass sample in duplicate.
Materials
- Z. mobilis 8b culture (available from the National Renewable Energy Lab (NREL))
- Glucose
- Xylose
- Yeast extract
- HK2PO4
- Tetracycline Stock (5mg/ml ethanol stock solution)
- Wiley mill or cyclone mill.
- Aluminum weigh trays
- Cellulase
- Beta-glucosidase
- 125ml flasks
- Gas traps for 125ml flasks
Procedure
Prepare the RMGXTc Medium
- Make RM media
- 90ml water
- 1g Yeast Extract
- 0.2g HK2PO4
- Make Sugar concentrate
- 10ml water
- 2g glucose
- 2g xylose
- Autoclave liquid medium and sugar concentrate.
- After cooling add sugar concentrate and 400μL tetracycline stock solution to medium.
Growing Zymomonas mobilis 8b
- Inoculate the medium with Z. mobilis from -80°C freezer stock.
- Grow with shaking for ~16 hours at 30°C.
Preparing the Biomass
- Collect 25g of biomass.
- If you want you can grind the samples using a wiley mill or a cyclone mill
- The samples will have to be less than 20% moisture to grind (i.e. they will have to be pretty dry).
- If analyzing multiple different samples the mill should be cleaned out between samples to avoid cross contamination.
- Add ≈2g of dry cellulose to two 125 ml flasks. (record these weights)
- This usually works out to be ≈10g of silage
- Number and weigh two aluminum weigh trays. (record these weights)
- Add ≈1g of biomass to each aluminum tray. (also record these weights)
- Put the aluminum trays in the 105°C oven overnight allow to cool.
- Weight the aluminum trays (with the dried biomass) after cooling (this will be done after your fermentation has started).
- Calculate the moisture content by the following equation
- %Moisture content (%wet basis) = 100*[(initial biomass weight + tray weight - final biomass weight and tray weight) / (Initial biomass weight + tray weight)]
- This will allow you to determine the exact amount of dry biomass you added to each flask
Preparing the SSCF Medium
- Combine the following and autoclave:
- 80ml water
- 1g Yeast Extract
- 0.2g HK2PO4
- 1g trisodium citrate dihydrate
- 0.33g citric acid monohydrate
- Chaekc that the pH is around 5.5
- Autoclave the medium
- After autoclaving and cooling add the following:
- 40FPU Cellulase
- 240IU Beta-Glucosidase
- 200μL Tetracycline stock
Running the Fermentation
- Add 40mL of the SSCF solution to the flasks containing the 2g dry cellulose (10g silage).
- Seal flasks with gas trap
- Incubate with shaking for 5 days at 30-37°C
- Measure ethanol production using a YSI 2700 Select Biochemistry Analyzer.