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Abstract Background In the normal process of bioethanol production, biomass is transported to integrated large factories for degradation to sugar, fermentation, and recovery of ethanol by distillation. Biomass nutrient loss occurs during preservation and degradation. Our aim was to develop a decentralized ethanol production system appropriate for farm or co-operative level production that uses a solid-state fermentation method for producing bio-ethanol from whole crops, provides cattle feed, and produces no wastes. The idea is to incorporate traditional silage methods with simultaneous saccharification and fermentation. Harvested, fresh biomass is ensiled with biomass-degrading enzymes and yeast. Multiple parallel reactions for biomass degradation and ethanol and lactic acid production are induced in solid culture in hermetically sealed containers at a ranch. After fermentation, ethanol is collected on site from the vapor from heated fermented products. Results The parallel reactions of simultaneous saccharification and fermentation were induced efficiently in the model fermentation system. In a laboratory-scale feasibility study of the process, 250 g of freshly harvested forage rice with 62% moisture was treated with 0.86 filter paper units/g dry matter (DM) of cellulase and 0.32 U/g DM of glucoamylase. After 20 days of incubation at 28°C, 6.4 wt.% of ethanol in fresh matter (equivalent to 169 g/kg DM) was produced. When the 46 wt.% moisture was gathered as vapor from the fermented product, 74% of the produced ethanol was collected. Organic cellular contents (such as the amylase and pronase degradable fractions) were decreased by 63% and organic cell wall (fiber) content by 7% compared to silage prepared from the same material. Conclusions We confirmed that efficient ethanol production is induced in nonsterilized whole rice plants in a laboratory-scale solid-state fermentation system. For practical use of the method, further study is needed to scale-up the fermentation volume, develop an efficient ethanol recovery method, and evaluate the fermentation residue as an actual cattle feed.

4-Hydroxy-3-methyl-2(1 H )-quinolone ( 1 ), a molecule known for a long time and recently discovered from a Brassicaceae plant Isatis tinctoria without providing sufficient evidence to support the structure, was isolated from a fermentation extract of Burkholderia sp. 3Y-MMP isolated from a soil by a Zn 2+ enrichment culture. Detailed spectroscopic analyses by MS and NMR, combined with 13 C chemical shift comparison with literature values of the related compounds and a synthetic preparation of 1 , allowed its first full NMR characterization and identification of 2-quinolone but not 2-quinolinol ( 2 ) as the preferred tautomer for this heterocyclic system. While the metal-chelating activity was negligible, compound 1 at 10 μM, a concentration lower than that in liquid production cultures, quenched hydroxy radical-induced chemiluminescence emitted by luminol by 86%. Because some Burkholderia species are pathogenic to plants and animals, the above result suggests that 1 is a potential antioxidant to counteract reactive oxygen species-based immune response in the host organisms., (Copyright © 2020, Li et al.; licensee Beilstein-Institut.)

Siderophores are considered to have a good potential as decontamination agents owing to their metal-chelating abilities. In order to confirm whether siderophores can be used in the recovery of metal ions, a siderophore (or metallophore) exhibiting Co 2+ -chelating activity was screened to demonstrate its ability to recover Co 2+ from an aqueous solution. A siderophore-producing bacterium, Pandoraea sp. HCo-4B, was identified from a screen of Co 2+ -resistant bacteria grown in an aerobic enrichment culture with a Co 2+ -supplemented medium. After incubation of the crude extracted siderophore in a Co 2+ -containing solution, the Co 2+ -siderophore complex was adsorbed on to a C 18 column. The bound Co 2+ was eluted from the column by the addition of 10 mM H 2 SO 4 . The recovered amount of Co 2+ was proportional to the amount of the added siderophore. We observed that the siderophore identified in this study binds to Co 2+ at a 1:1 ratio.