Hydrophilic compounds in liquids of enzymatic hydrolyzed spruce and pine biomass.

Organic acids are used for starting compounds in material sciences and in biorefinery, food, fuel, pharmaceutical, and medical industry. Here, we provide the data from a biochemical approach made to investigate production of organic acids and isolation of metals from wood, which is the most abundant biomass. Spruce and bark, phloem, and heartwood from pine were fermented with either microbes of oyster mushroom (Pleurotus ostreatus), baker's yeast, or lactic acid bacteria to improve selective fermentation. Using capillary electrophoresis and liquid chromatography techniques, we identified 14 different organic acids and phenolic acids with good yields. With inductively coupled plasma atomic emission spectroscopy 11 metals were quantified and further detailed analysis/results from these data are available in Sirén et al. (2015) [1].

Specifications Table

Value of the data

New route for production of chemicals from softwood can be used for polymers and biomaterials

Green chemistry production for materials with microbes can be applied for manufacturing biodegradable products and cleantech materials

Processes are more widely applicable for integration to biorefinery

The diverse separation technology for water-soluble bioproducts will be useful for other researchers who are developing food preservatives, hygienic products, antibacterial products and medicines for self-care drugs.

Data

The data shown is schemes and a photograph explaining details of pretreatment and microreactor devices used to process the pine materials. The chromatograms, electropherograms, histograms, and the table show the profiling of the biofluids, the efficiency of the Oyster mushroom against some other microbes, and the quantities of the most important acids in hydrolyzed heartwood, bark, and phloem of pine.

Experimental design and materials

Hydrophilic organic acids in fresh spruce and pine wood extracts were studied after processing them in bioreactors in the presence of microbes from oyster mushroom (Pleurotus ostreatus) or enzymes from dried yeast (Saccharomyces cerevisiae). The organic acids were extracted from sorted-out wood material. Metals were also studied, but only after the wood was oven-dried. In the case of no dried samples, the purpose was to use the natural microbes of the fresh trees (Fig. 1).

Fig.1

Overall workflow of the samples.

Methods

The methods used were ICP-AES, inductively coupled plasma atomic emission spectroscopy; CE, capillary electrophoresis; UV, ultraviolet spectrophotometry; HPLC, high-performance liquid chromatography; DAD, diode array detection; MAE, microwave-assisted extraction; bioreactor fermentation (Figs. 2 and 3); acid hydrolysis.

The bioreactor process was optimized for extraction of hydrophilic organic acids in fresh spruce and pine wood. The products were processed at the presence of microbes from oyster mushroom (P. ostreatus) or alternatively with enzymes from dried yeast (S. cerevisiae) (Fig. 4). The wood materials were sorted-out from softwood. The fluids contain innumerable amounts of various kinds of organic compounds. Because of the similarity of their structures, the top value-added organic acids and chemicals need to be separated (Figs. 5 and 6) for identification and quantification.

Fig. 4

Comparison of fermentation microbes based on extraction time using total carbon concentration (TC). Fermentation with yeast and tartaric acid were used to compare their ability to that of oyster mushroom. The two first are used in well-known wine fermentation and ethanol production. Oyster mushroom worked efficiently only in the first day for acid formation [1].

Metals were also studied from oven-dried woods. In the case of non-dried samples the purpose was to use the natural microbes of the fresh trees and to minimize the material costs. First of all, the added microbes needed to work in fast degradation of lignin, hemicelluloses, cellulose, and polysaccharides.

The acids were mainly localized in both skin and pulp of the wood (Fig. 7). Table 1 also provides an overview of the main organic acids in the fermentation processes of spruce and pine by CE and HPLC.

Fig. 7

Main organic acids and metals in the heartwood, bark, and phloem of pine: (A) organic acids with CE. The organic acids without aromatic rings were separated in an electrolyte solution, which contained 20 mM 2,3-pyrazinedicarboxylic acid (2,3 PDC), 0.3 mM MTAH, and 30 mg/L of both Ca2+ and Mg2+ in MeOH–water solution (10:90, v/v) at pH 9.0; (B) metals with ICP-EAS. [1].

Table 1

Production of the main organic acids in fermentation processes of spruce and pine analyzed with CE and HPLC. [1].

Organic acid	Processed (g/kg)	Wood type
L-Lactic acid (S. cerevisiae)	0.36	Mix, spruce
L-Malic acid (S. cerevisiae)	0.45	Mix, spruce
Succinic acid (P. ostreatus)	0.89	Bark+phloem+heartwood, pine
Adipic acid (P. ostreatus)	7.05	Bark+phloem+heartwood, pine
Citric acid (P. ostreatus)	3.61	Bark+phloem+heartwood, pine

Subject area	Chemistry
More specific subject area	Biomaterials, biocompounds, forest chemistry
Type of data	Tables, text files, figures
How data was acquired	Two capillary electrophoresis instruments (P/ACE MDQ capillary electrophoresis, SCIEX, Beckman Coulter, Fullerton, CA, USA) both coupled with a photodiode array detector (PDA).
Two liquid chromatograph instruments (1260 Infinity Quaternary LC System and 1100 LC System, Agilent Technologies, Waldbronn, Germany) both on-line coupled with a diode array detector (DAD, HP 1100 LC).
The gas chromatograph – mass spectrometer instrument (GC–MS/MS instrument, Agilent Technologies 7890 A GC System) coupled with an Agilent Technologies 7000 GC/MS Triple Quad (Agilent Technologies, Waldbronn, Germany). The Agilent Technologies 7693 Autosampler, the MassHunter Workstation Software, and the NIST Mass Spectral Search Program 2.0.
An ICP-AES instrument (IRIS Interpid II XDL (Thermo Fisher Scientific, Vantaa, Finland).
Microwave-assisted extraction (MAE) instrument (Anton PAAR, USA).
Three different bioreactors (vol. 0.5 L, 2 L, and 3.5 L (laboratory-made instruments).
Data format	Raw data
Experimental factors	Organic compounds were produced from wood in the bioreactors with either microbes of oyster mushroom (P. ostreatus), baker’s yeast, or lactic acid bacteria. The compounds were analyzed straight from the fluids. Metals were isolated with MAE.
Experimental features	The samples are pieces from logs of living trees. They were pretreated with a gentle fermentation.
Data source location	Helsinki, Finland and Lappeenranta, Finland
Data accessibility	The data are with this article.