Measurement of the inhibitory potential and detoxification of biomass pretreatment hydrolysate for ethanol production

Journal Article · Tue Dec 31 04:00:00 EST 1996 · Applied Biochemistry and Biotechnology

DOI:https://doi.org/10.1007/BF02941698· OSTI ID:598207

Rivard, C J; Engel, R E; Nagle, N J ^[1]

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1. National Renewable Energy Lab., Golden, CO (United States); and others

The Microtox assay represents a rapid, accurate, and reproducible method for determining general microbial toxicity. This assay was used to evaluate the relative toxicity of a variety of hydrolysate samples derived from dilute-acid and alkaline biomass pretreatment. Toxicity is elicited from biomass degradation products, such as furfural, hydroxymethyl furfural, and acetic acid, generated during pretreatment. Microtox results indicate that the pretreatment samples examined ranged from 9 to 71 toxicity units (TU). Correlations of TU and sample absorbance at several wavelengths were evaluated for all sample series. Sample TU values best agreed with absorbance at 230 nm, but the unsatisfactory fit suggests that absorbance should not be used as an absolute measure of sample toxicity. Microtox data for pretreatment hydrolysate samples were correlated with the inhibition experienced by the ethanologenic yeast, Saccharomyces cerevisiae strain D{sub 5}A, during the simultaneous saccharification and fermentation (SSF) process of pretreated biomass. None of the alkaline pretreatment conditions produced inhibition during SSF. However, the acid pretreatment conditions did produce a wide range of inhibitory and noninhibitory hydrolysates. In general, fermentation was inhibited for acid-pretreated hydrolysate samples with values exceeding 45 TU. Preliminary studies that focused on reducing hydrolysate sample toxicity (detoxification) indicate that adding perlite and zeolite had little effect. However, the use of charcoal, a universal flocculent, or ion-exchange resins significantly reduced sample toxicity, holding promise for the efficient bioconversion of pretreated biomass to ethanol. Moreover, the developed toxicity measurement assay can quickly monitor the quality of the pretreatment process. In this way, biomass conversion operation processes can be reliably controlled at the pilot and commercial scales. 4 refs., 4 figs., 3 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 598207
• Report Number(s): CONF-950587--
• Journal Information: Applied Biochemistry and Biotechnology, Journal Name: Applied Biochemistry and Biotechnology Vol. 57-58; ISSN ABIBDL; ISSN 0273-2289
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
55 BIOLOGY AND MEDICINE
BASIC STUDIES
ACCURACY
ACETIC ACID
BIOCONVERSION
BIODEGRADATION
BIOMASS
CHARCOAL
CORRELATIONS
DETOXIFICATION
EFFICIENCY
ETHANOL
FERMENTATION
FLOCCULATION
FURFURAL
HYDROLYSIS
INHIBITION
ION EXCHANGE
NATIONAL RENEWABLE ENERGY LABORATORY
PRODUCTION
QUALITATIVE CHEMICAL ANALYSIS
QUALITY ASSURANCE
REDUCTION
RELIABILITY
RENEWABLE ENERGY SOURCES
SACCHARIFICATION
SACCHAROMYCES CEREVISIAE
TOXICITY