fermentation residues of molasses, yeast extract, sucrose and ammonia with bacillus subtilis

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29-oct-2009 to 11-jan-2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Biomass residue (liquid) obtained after B2 production

IUPAC Name:

Biomass residue (liquid) obtained after B2 production

Method

Target gene:

- S. typhimurium: Histidine gene
- E. coli: Tryptophan gene

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

Rat liver S9-mix induced by a combination of phenobarbital and ß-naphthoflavone

Test concentrations with justification for top dose:

Experiment 1:
Preliminary test (without and with S9) TA100 and WP2uvrA: 3, 10, 33, 100, 333, 1000, 3330 and 5000 µg/plate
Main study: TA1535, TA1537 and TA98:
Without and with S9-mix: 100, 333, 1000, 3330 and 5000 µg/plate
Experiment 2:
All tester strains:
Without and with S9-mix: 100, 333, 1000, 3330 and 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: A suspension was obtained with DMSO and DMSO is accepted and approved by authorities and international guidelines.

Controls

Controls 1

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

without S9

Migrated to IUCLID6: : 5 µg/plate in saline for TA1535

Controls 2

Positive control substance:

9-aminoacridine

Remarks:

without S9

Migrated to IUCLID6: : 60 µg/plate in water for TA1537

Controls 3

Positive control substance:

2-nitrofluorene

Remarks:

without S9

Migrated to IUCLID6: : 10 µg/plate in DMSO for TA98

Controls 4

Positive control substance:

methylmethanesulfonate

Remarks:

without S9

Migrated to IUCLID6: : 650 µg/plate in DMSO for TA100

Controls 5

Positive control substance:

4-nitroquinoline-N-oxide

Remarks:

without S9

Migrated to IUCLID6: : 10 µg/plate in DMSO for WP2uvrA

Controls 6

Positive control substance:

other: 2-aminoanthracene in DMSO for all tester strains

Remarks:

with S9

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 hour

NUMBER OF REPLICATIONS:
- Doses of the test substance were tested in triplicate in each strain. Two independent experiments were conducted.

NUMBER OF CELLS EVALUATED: 10E8 per plate

DETERMINATION OF CYTOTOXICITY
- Method: The reduction of the bacterial background lawn, the increase in the size of the microcolonies and the reduction of the revertant colonies.

OTHER EXAMINATIONS:
- The presence of precipitation of the test compound on the plates was determined.

Evaluation criteria:

A test substance is considered negative (not mutagenic) in the test if:
a) The total number of revertants in tester strain TA100 is not greater than two (2) times the concurrent control, and the total number of revertants in tester strains TA1535, TA1537, TA98 or WP2uvrA is not greater than three (3) times the concurrent control.
b) The negative response should be reproducible in at least one independently repeated experiment.

A test substance is considered positive if:
b) A two-fold (TA100) or more or a three-fold (TA1535, TA1537, TA98, WP2uvrA) or more increase above solvent control in the mean number of revertant colonies is observed in the test substance group.
b) The increase in the mean number of revertant colonies follows the concentration of test substance (dose-response relationship).

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

: tested up to the top dose of 5000 µg/plate

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

: tested up to the top dose of 5000 µg/plate

Vehicle controls validity:

valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
-Precipitation: No precipitation was observed up to and including the top of 5000 µg/plate

RANGE-FINDING/SCREENING STUDIES:
- No toxicity was observed up to and including the top dose of 5000 µg/plate

COMPARISON WITH HISTORICAL CONTROL DATA:
- The negative and strain-specific positive control values were within our laboratory historical control data ranges indicating that the test conditions were adequate and that the metabolic activation system functioned properly.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

All bacterial strains showed negative responses over the entire dose range, i.e. no significant dose-related increase in the number of revertants in two independently repeated experiments. Based on the results of this study it is concluded that Biomass residue (liquid) obtained after B2 production is not mutagenic in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay.