Hydrogen Production from Barley Straw and Miscanthus by the Hyperthermophilic Bacterium, Cadicellulosirupter bescii.

This work aimed to evaluate the feasibility of biohydrogen production from Barley Straw and Miscanthus. The primary obstacle in plant biomass decomposition is the recalcitrance of the biomass itself. Plant cell walls consist of cellulose, hemicellulose, and lignin, which make the plant robust to decomposition. However, the hyperthermophilic bacterium, Caldicellulosiruptor bescii, can efficiently utilize lignocellulosic feedstocks (Barley Straw and Miscanthus) for energy production, and C. bescii can now be metabolically engineered or isolated to produce more hydrogen and other biochemicals. In the present study, two strains, C. bescii JWCB001 (wild-type) and JWCB018 (ΔpyrFA Δldh ΔcbeI), were tested for their ability to increase hydrogen production from Barley Straw and Miscanthus. The JWCB018 resulted in a redirection of carbon and electron (carried by NADH) flow from lactate production to acetate and hydrogen production. JWCB018 produced ~54% and 63% more acetate and hydrogen from Barley Straw, respectively than its wild-type counterpart, JWCB001. Also, 25% more hydrogen from Miscanthus was obtained by the JWCB018 strain with 33% more acetate relative to JWCB001. It was supported that the engineered C. bescii, such as the JWCB018, can be a parental strain to get more hydrogen and other biochemicals from various biomass.

Investigation of suitable seed sizes, segregation of ripe seeds, and improved germination rate for the commercial production of hemp sprouts (Cannabis sativa L.).

BACKGROUND: With a growing market for functional foods, the nutraceutical properties of hemp sprouts have been investigated in recent studies. However, commercial mass production methods have yet to be developed. This study aimed to identify seed sizes suitable for segregating ripe seeds, which would improve the low germination rate in the high seed densities used in commercial hemp sprout production. RESULTS: Seeds ranging in size from 2.80 to 3.3 mm, collected by sieving, were the most suitable for sprouting, based on the distribution rate (74.9%) and germination rate (70.0%) at a low seed density (0.016 grains mm-2 ). Seed segregation by sinking the seeds in 70% ethanol after 2 h or more of water infiltration generated high germination rates of 86.3% to 94.3% at low seed density, compared to a 64.0% germination rate in non-segregated seeds. The hemp seed germination rate decreased geometrically with increasing sowing density. The germination rate with a high seed density (0.29 grains mm-2 ) was increased from 19.9% when seeds were not mixed with sand to 58.7% when mixed with sand in a 3:1 ratio. The sprouting yield significantly increased from 1.64 kg kg-1 when seeds were not mixed with sand to 9.55 kg kg-1 in seeds germinating when mixed with sand. Delta-9-tetrahydrocannabinol was not detected in hemp sprout. CONCLUSION: The production of hemp sprouts may be improved by identifying suitable seed sizes, segregating ripe seeds, and germinating seeds mixed with sand. This can be used in the commercial production of hemp sprouts. The sprouts were also found to be safe and without hallucinogenic effects. © 2020 Society of Chemical Industry.

Silver grass-derived activated carbon with coexisting micro-, meso- and macropores as excellent bioanodes for microbial colonization and power generation in sustainable microbial fuel cells.

In this study, highly biocompatible three-dimensional hierarchically porous activated carbon from the low-cost silver grass (Miscanthus sacchariflorus) has been fabricated through a facile carbonization approach and tested it as bioanode in microbial fuel cell (MFC) using Escherichia coli as biocatalyst. This silver grass-derived activated carbon (SGAC) exhibited an unprecedented specific surface area of 3027 m2 g-1 with the coexistence of several micro-, meso-, and macropores. The synergistic effect from pore structure (macropores - hosting E. coli to form biofilm and facilitates internal mass transfer; mesopores - favors fast electron transfer; and micropores - promotes nutrient transport to the biofilm) with very high surface area facilitates excellent extracellular electron transfer (EET) between the anode and biofilm which resulted in higher power output of 963 mW cm-2. Based on superior biocompatibility, low cost, environment-friendliness, and facile fabrication, the proposed SGAC bioanode could have a great potential for high-performance and cost-effective sustainable MFCs.

Hydrothermal-process-based direct extraction of polydisperse lignin microspheres from black liquor and their physicochemical characterization.

Lignin nano-/microstructures are widely employed for agricultural drug delivery and heavy metal removal from wastewater, and facile low-cost methods of their large-scale production are therefore highly sought after. Herein, uniform-morphology polydisperse lignin microspheres were directly extracted from black liquor by lowering its pH to <4 followed by hydrothermal treatment and featured several lignin-typical characteristics, e.g., functional groups, thermal stability, amorphousness, and monolignol units. It was assumed that lignin rearranged and assembled into microspheres of various size, shape, and uniformity depending on pH, temperature, and hydrothermal treatment time. Lignin microsphere extraction efficiency was estimated as 15.87-21.62 g L-1, and the average size of microspheres obtained under different conditions was calculated as ∼1 µm, while the C, H, O, and N contents equaled 48-62, 5-6, 30-36, and 0.2-1.5%, respectively. Thus, our method was deemed suitable for direct large-scale extraction of lignin microspheres from black liquor.

The optimal mixing ratio of Brassica napus and Brassica juncea meal improve nematode Meloidogyne hapla effects.

The use of rapeseed (Brassica napus L.) or leaf mustard (Brassica juncea L. Czern) meal or both as organic fertilizer not only improves the soil environment and crop productivity by supplying nutrients but also has nematicidal effects. This study aimed to establish the optimal application levels of rapeseed and leaf mustard meal for stronger nematode control in tomato. Tomato is one of the most important solanaceous crops which is severely damaged by nematodes. At first, meal (120 g of varying mixing ratios of rapeseed and leaf mustard meal) was mixed with sterilized soil (1 kg). The optimal ratio of rapeseed:leaf mustard meal for effective nematode control was 20:100 g/kg of soil. Progoitrin and gluconapin were the most abundant glucosinolates found in rapeseed meal, while sinigrin was the most abundant in leaf mustard meal. The amount of sinigrin increased if the leaf mustard meal proportion increased in the meal mixture. Although the content of sinigrin in optimal ratio mixture of rapeseed and leaf mustard meal is lower than only leaf mustard meal, it is presumed that nematocidal effects of the mixture are better than that of the single component due to the high contents of progoitrin and gluconapin. So, we propose that rapeseed and leaf mustard meal mixture at an appropriate ratio can be used as an environmentally friendly nematocide.

Bioethanol production from cellulosic hydrolysates by engineered industrial Saccharomyces cerevisiae.

Even though industrial yeast strains exhibit numerous advantageous traits for the production of bioethanol, their genetic manipulation has been limited. This study demonstrates that an industrial polyploidy Saccharomyces cerevisiae JHS200 can be engineered through Cas9 (CRISPR associated protein 9)-based genome editing. Specifically, we generated auxotrophic mutants and introduced a xylose metabolic pathway into the auxotrophic mutants. As expected, the engineered strain (JX123) enhanced ethanol production from cellulosic hydrolysates as compared to other engineered haploid strains. However, the JX123 strain produced substantial amounts of xylitol as a by-product during xylose fermentation. Hypothesizing that the xylitol accumulation might be caused by intracellular redox imbalance from cofactor difference, the NADH oxidase from Lactococcus lactis was introduced into the JX123 strain. The resulting strain (JX123_noxE) not only produced more ethanol, but also produced xylitol less than the JX123 strain. These results suggest that industrial polyploidy yeast can be modified for producing biofuels and chemicals.

Continuous alkaline pretreatment of Miscanthus sacchariflorus using a bench-scale single screw reactor.

Miscanthus sacchariflorus 'Goedae-Uksae 1' (GU) was developed as an energy crop of high productivity in Korea. For the practical use of GU for bioethanol production, a bench-scale continuous pretreatment system was developed. The reactor performed screw extrusion, soaking and thermochemical pretreatment at the following operating conditions: 3 mm particle size, 22% moisture content, 140 °C reaction temperature, 8 min residence time, 15 g/min biomass feeding and 120 mL/min NaOH input. As a result of minimizing NaOH concentration and enzyme dosage, 90.8±0.49% glucose yield was obtained from 0.5 M NaOH-pretreated GU containing 3% glucan with 10 FPU cellulase/g cellulose at 50 °C for 72 h. The separate hydrolysis and fermentation of 0.5 M NaOH-pretreated GU containing 10% glucan with 10-30 FPU for 102 h produced 43.0-49.6 g/L bioethanol (theoretical yield, 75.8-87.6%). Thus, this study demonstrated that continuous pretreatment using a single screw reactor is effective for bioethanol production from Miscanthus biomass.

The optimized CO2-added ammonia explosion pretreatment for bioethanol production from rice straw.

A CO2-added ammonia explosion pretreatment was performed for bioethanol production from rice straw. The pretreatment conditions, such as ammonia concentration, CO2 loading level, residence time, and temperature were optimized using response surface methodology. The response for optimization was defined as the glucose conversion rate. The optimized pretreatment conditions resulting in maximal glucose yield (93.6 %) were determined as 14.3 % of ammonia concentration, 2.2 MPa of CO2 loading level, 165.1 °C of temperature, and 69.8 min of residence time. Scanning electron microscopy analysis showed that pretreatment of rice straw strongly increased the surface area and pore size, thus increasing enzymatic accessibility for enzymatic saccharification. Finally, an ethanol yield of 97 % was achieved via simultaneous saccharification and fermentation. Thus, the present study suggests that CO2-added ammonia pretreatment is an appropriate process for bioethanol production from rice straw.

A new genotype of Miscanthus sacchariflorus Geodae-Uksae 1, identified by growth characteristics and a specific SCAR marker.

Miscanthus is referred to as an ideal lignocellulosic bioenergy crop, which can be used to generate heat, power, and fuel, as well as to reduce carbon dioxide emissions. The new Miscanthus sacchariflorus genotype named Geodae-Uksae 1 was recently collected from damp land in southern Korea. This study investigated the growth characteristics of Miscanthus genotypes, and developed a specific, sensitive, and reproducible sequence characterized amplified region (SCAR) marker to distinguish new M. sacchariflorus genotype Geodae-Uksae 1 from other native Miscanthus species in Korea. Growth characteristics such as stem length, stem diameter, and dry weight of Geodae-Uksae 1 were greater than those of normal M. sacchariflorus. The genotypes within Geodae-Uksae 1 were had the highest genetic similarity. A putative 1,800-bp polymorphic sequence specific to Geodae-Uksae 1 was identified with the random amplified polymorphic DNA (RAPD) N8018 primer. The sequence-characterized amplified region (SCAR) primers Geodae 1-F and Geodae 1-R were designed based on the unique RAPD amplicon. The SCAR primers produced a specific 1,799-bp amplicon in authentic Geodae-Uksae 1, whereas no amplification was observed in other Miscanthus species. The SCAR marker could contribute to identify Geodae-Uksae 1 among native Miscanthus species. The new Miscanthus genotype Geodae-Uksae 1 has great potential as an alternative lignocellulosic biomass feedstock for bioenergy productions.

Development of SCAR marker for simultaneous identification of Miscanthus sacchariflorus, M. sinensis and M. x giganteus.

The sequence-characterized amplified region (SCAR) marker for simultaneous identification of Miscanthus sacchariflorus, Miscanthus sinensis, and Miscanthus x giganteus was developed. In this study, it was attempted for the first time to develop the SCAR marker for detecting the molecular phenotypes among Miscanthus species. Randomly amplified polymorphic DNA technique was applied for this study and one fragment which is unique to M. sacchariflorus was identified and then sequenced. Based on the specific fragment, one SCAR primer pair designated as MS62-5F and MS62-5R was designed to amplify an approximately 1,000 bp DNA fragment within the sequenced region. Diagnostic PCR was performed using the primer pair. Using this SCAR marker, approximately 1,000 bp and 1,200 bp DNA fragments were obtained in M. sacchariflorus and M. sinensis, respectively. Moreover, M. x giganteus was obtained both bands at the same time. The result showed that this SCAR marker can clearly distinguish the M. sacchariflorus, M. sinensis, and M. x giganteus, respectively.