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Title: Black Liquor Valorization by Using Marine Protist Thraustochytrium striatum and the Preliminary Metabolic Mechanism Study

Journal Article · · ACS Sustainable Chemistry & Engineering
 [1]; ORCiD logo [2];  [3]; ORCiD logo [4]; ORCiD logo [1]
  1. Kansas State Univ., Manhattan, KS (United States)
  2. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemical and Biomolecular Engineering
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Joint Inst. of Biological Science
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Joint Inst. of Biological Science; Univ. of Tennessee, Knoxville, TN (United States)

Black liquor that contains various phenolic compounds from lignin solubilization has been the main byproduct of alkaline pretreatment of lignocellulosic biomass in the biorefinery. In this study, black liquor from alkaline pretreatment of corn stover was used as a sole carbon source for the cultivation of a marine protist, Thraustochytrium striatum. It was found that this strain can grow on black liquor and accumulate valuable products (e.g., fatty acids and carotenoids) simultaneously. Under optimal conditions (pH = 7 and NH4Cl = 2 g/L), the cell mass concentration reached 5.2 g/L with total aromatics decreased from 8.18 to 3.09 g/L within 7 day incubation. Fed-batch cultivation was adopted to increase the contents of total fatty acids and carotenoids to 13% and 0.24 mg/g dry cell mass, respectively. Although various compounds such as sugars and organic acids were detected in black liquor and consumed during microbial fermentation as carbon sources, lignin-derived compounds were identified as the major substrates for T. striatum fermentation. Of total aromatics consumed, monomers including p-coumaric acid, ferulic acid, vanillin, and syringaldehyde were observed to be consumed and converted while polymeric fragments were also depolymerized and degraded. Under optimal conditions, around 50% of the total aromatics was consumed. The dynamic changes of compounds in black liquor indicated that diverse metabolic processes were involved in black liquor degradation and utilization by T. striatum. A strong adaptation of T. striatum to a wide range of pH (3–9) was also observed during black liquor fermentation.

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Grant/Contract Number:
AC05-00OR22725
OSTI ID:
1606660
Journal Information:
ACS Sustainable Chemistry & Engineering, Journal Name: ACS Sustainable Chemistry & Engineering Journal Issue: 4 Vol. 8; ISSN 2168-0485
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English