Industrial demonstration plant for the gasification of herb residue by fluidized bed two-stage process

Matured compost amendment improves compost nutrient content by changing the bacterial community during the composting of Chinese herb residues

Composting is a sustainable strategy to deal with organic waste. Our research aimed to study the influence of an amendment of 10% matured compost (MC) during Chinese herb residue (CHR) compost. Here, a 60-day CHR compost was performed, and MC application was able to reduce the nitrogen loss and enhance the humic acid accumulation during the composting as compared with the non-inoculated control (NC), by 25 and 19%, respectively. Furthermore, the matured compost amendment improved the diversity of the bacterial community, increased the complexity of the co-occurrence network, and changed the keystone and module hub bacteria during composting. The increased abundance levels of Thermopolyspora, Thermobispora, and Thermosporomyces, which were significantly higher in MC than in NC, may contribute to the degradation of cellulose and the formation of humic acid. Overall, this study extends our understanding of the effects of matured compost reflux on compost quality and the bacterial community.

Treatment and bioresources utilization of traditional Chinese medicinal herb residues: Recent technological advances and industrial prospect

Traditional Chinese medicine (TCM) has wide application and important functions in curing many diseases, but a great number of herb residues are usually generated after its manufacture and usage. Without proper and timely treatment, these traditional Chinese medicinal herb (TCMH) residues will cause some environmental pollution. In addition to treatment, bioresources utilization of TCMH residues is also important for its great potential as a suitable feedstock for the production of energy, materials, and chemicals. In this situation, advanced and well-designed solid waste management is important to make the TCM industry environmentally friendly and economically attractive. In this review article, the recent progress focusing on various methods for TCMH residues treatment and bioresources utilization are introduced in detail. In particular, the technologies for thermochemical conversion and biochemical conversion of TCMH residues are mainly focused on in order to show how to fulfill effective and efficient bioresources utilization. Besides, some other technologies which are suitable for the treatment and bioresources utilization of TCMH residues are presented as well. Finally, some industrial prospects are given from the economic, operational, and environmental aspects for the further development of treatment and bioresources utilization of TCMH residues. Overall, this work can provide some systematical and comprehensive information for the development of technologies that help sustainably manage the herb residues generated in the TCM industry.

A novel green synthesis of silver nanoparticles by the residues of Chinese herbal medicine and their biological activities

Green synthesis of silver nanoparticles (AgNPs) by using the extracts of Chinese herbal medicines (CHMs) has attracted tremendous attention due to the potential synergistic effect between metal nanoparticles and capping agents. However, since CHMs are precious and expensive, finding other cheap and eco-friendly resources for biosynthesizing AgNPs with superior medicinal activites is necessary. Herbal medicine residues (HMRs) are the by-products of traditional Chinese herbal medicine after decoction and were identified to contain approximately 30-50% of medicinally active ingredients, which may be advantageous for green synthesis of medicinal AgNPs. Inspired by this, we present herein the preparation of AgNPs by reusing Bazheng Mixture residues and evaluate both biosynthesis parameters and bioactivities, where Bazheng Mixture is a famous Chinese patent medicine for relieving inflammation and pain, and allaying fever. The UV-visible spectrum and DLS analysis showed that the as-prepared AgNPs were sensitive to pH, material proportion and incubation time, but the yield was impervious to material proportion. TEM, HRTEM, SAED and DLS characterization found that AgNPs (pH 10.0; material proportion 1 : 1; 6 h) had a face-centered cubic (fcc) structure and spherical shape with an average size of 22.2 ± 0.5 nm covered by anions, and existed in monodispersed form with long term stability. The AgNPs displayed potent toxic effects against both cancer cell lines and pathogens, and superior antioxidant activity. The IC50 for HCT116, HepG2 and HeLa cell lines were 13.07, 19.67, and 26.18 μg mL-1, respectively. The MICs of AgNPs for E. coli and S. aureus were both 50.0 μg mL-1. The uptake analysis of AgNPs for both pathogens and cancer cell lines was performed to preliminarily illustrate the mechanism of toxic effects. These results confirm that HMRs could be a low-cost, nontoxic and eco-friendly resource for green synthesis of medicinal AgNPs, and also provide an alternative method for general recycling strategies of HMRs.

Exploring the silage quality of alfalfa ensiled with the residues of astragalus and hawthorn

This study evaluated the effect of astragalus (AS) and hawthorn (HN) residues on the silage quality of alfalfa. Alfalfa was ensiled with additives (AS, HN and AS + HN) or without additives for 60 days. Results showed that the silage treated with AS and HN had lower contents of butyric acid and NH₃-N compared with control, whereas no significant differences of pH and lactic or acetic acid content were found. Additionally, the treated silages also exhibited lower copy numbers of Clostridium, Enterobacter and fungi during ensiling process established by qPCR. In conclusion, AS and HN could be used as additives to control the growth of unfavorable microorganism and enhance the silage quality.

Recycling of Chinese herb residues by endophytic and probiotic fungus Aspergillus cristatus CB10002 for the production of medicinal valuable anthraquinones

Background

The global prevalence of traditional Chinese medicine stimulates the prosperous development of herb medicines, but the annual generation of massive herb residues becomes big issues about environmental pollution and waste of resources. Microbes play important roles in the circulation of substances in nature, and endophytes represent an underexplored microbial resource possessing the unique symbiotic relationship with plants, not only for discovery of secondary metabolites, but also for potential green recycling of herb residues.

Results

The recycling capacities of several endophytic strains were respectively evaluated via solid state fermentation with herb residues of commercial Huazhenghuisheng oral-liquid (HOL). Among them, Aspergillus cristatus CB10002, a probiotic fungus isolated from Chinese Fu-brick tea, was competent to recycle HOL residues for the production of medicinal valuable anthraquinones, in which four of them, especially citreorosein with significant anti-obesity activity, were first discovered in A. cristatus. Subsequent quantitative analysis showed that about 2.0 mg/g citreorosein and 7.5 mg/g total anthraquinones could be obtained after 35-day fermentation, which was very competitive and economically beneficial. Further nutritional comparisons also revealed that the recycling process indeed ameliorated the nutrients of HOL residues, and thus proposed a possibility to directly dispose the final leftovers as a compost organic fertilizer.

Conclusions

The endophytic and probiotic fungus A. cristatus CB10002 isolated from Chinese Fu-brick tea was screened out to effectively reutilize HOL residues for the production of nine medicinal valuable anthraquinones, whose biosynthesis may be regulated by the induction of HOL residues. The competitive yields of these anthraquinones, as well as the certain composting properties of final leftovers, have made the microbial recycling of HOL residues economically beneficial. Our work demonstrated a promising applied potential of A. cristatus in reutilization of herb residues, and provided a practical strategy for sustainable and value-added microbial recycling of herb residues.

Electronic supplementary material

The online version of this article (10.1186/s12934-019-1150-9) contains supplementary material, which is available to authorized users.

Biomass gasification for hydrogen rich gas in a decoupled triple bed gasifier with olivine and NiO/olivine

Catalytic steam gasification of biomass has been carried out in decoupled triple bed gasification (DTBG) system which consists of pyrolyzer, reformer and combustor. Olivine and NiO/olivine used as in-situ tar destruction catalyst. The result shows the gasification system with catalytic bed materials allows an option to improve tar removal that enhances H₂ production. A gas yield of 1.59 Nm³/kg daf with H₂ concentration of 56.1 vol% and tar content as low as 0.6 g/Nm³ has been achieved with the presence of NiO/olivine. Olivine and NiO/olivine reduced tar yield by 55% and 94% respectively compared to quartz. Gas yield, tar removal efficiency and water conversion enhanced by higher reformer temperature. The longer residences time of catalyst in reformer leads in-situ reduction of olivine and NiO/olivine that adds up in-situ tar reforming. Particularly, in-situ reduction of NiO to metallic Ni enhances tar and CH₄ reforming reaction.

A novel two-stage biomass gasification concept: Design and operation of a 1.5 MWth demonstration plant

To gasify the biofuel of low ash melting temperature and overcome the high content of tar in bio-gas, a novel two-stage gasification concept is proposed. This concept enables the tar-free bio-gas generated in the gasification process under thermal cracking. On that basis, a demonstration project is introduced. Rice husk acts as the feedstock for its accessibility on-site in the commissioning period. System reliability has been confirmed for the stable operation of more than 60 days. Tests have been performed under some typical operating conditions. As the results suggest, the bio-gas of 6.7 MJ/Nm³ LHV is generated with cold gas efficiency and carbon conversion of 67.5% and 87% respectively. Elementary economic evaluation of this concept is also made in accordance with the commissioning results. As a result, the annual net profit of 40.92 K USD is yielded without a subsidized price for biomass materials.

Characterization of herb residue and high ash-containing paper sludge blends from fixed bed pyrolysis

High ash-containing paper sludge which is rich in various metal oxides is employed in herb residue pyrolysis to enhance the yield of fuel gas and reduce tar yield in a drop tube fixed bed reactor. Effects of heat treatment temperature and blending ratio of paper sludge on the yields and composition of pyrolysis products (gas, tar and char) were investigated. Results indicate that paper sludge shows a significantly catalytic effect during the pyrolysis processes of herb residue, accelerating the pyrolysis reactions. The catalytic effect resulted in an increase in gas yield but a decrease in tar yield. The catalytic effect degree is affected by the paper sludge proportions, and the strongest catalytic effect of paper sludge is noted at its blending ratio of 50%. At temperature lower than 900 °C, the catalytic effect of paper sludge in the pyrolysis of herb residue promotes the formation of H₂ and CO₂, inhibits the formation of CH₄, but shows slight influence on the formations of CO, while the formation of the four gas components was all promoted at 900 °C. SEM results of residue char show that ash particles from paper sludge adhere to the surface of the herb residue char after pyrolysis, which may promote the pyrolysis process of herb residue for more gas releasing. FT-IR results indicate that most functional groups disappear after pyrolysis. The addition of paper sludge promotes deoxidisation and aromatization reactions of hetero atoms tars, forming heavier polycyclic aromatic hydrocarbons and leading to tar yield decrease.

Reclamation of Herb Residues Using Probiotics and Their Therapeutic Effect on Diarrhea

Residues from herbal medicine processing in pharmaceutical plants create a large amount of waste (herb residues), which consists mainly of environmental pollution and medicinal waste. In order to resolve this problem, probiotics of Bacillus (B.) subtilis, Aspergillus (A.) oryzae, and Lactobacillus (L.) plantarum M3 are selected to reuse herb residue of Jianweixiaoshi tablets (JT), and an antibiotic-associated diarrhea (AAD) mouse model was established to evaluate the therapeutic effects of the herb residue fermentation supernatant. Our results indicated that the fermentation supernatant had scavenged 77.8% of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 78% of O₂^•−, 36.7% of ^•OH, 39% of Fe²⁺ chelation, and 716 mg/L reducing power. The inhibition zones for Salmonella (S.) typhimurium, S. enteritidis, Shigella (Sh.) flexneri, Escherichia (E.) coli, Listeria (L.) monocytogenes, Sh. dysenteriae 301, and Staphylococcus (S.) aureus were 17, 14, 19, 18, 20, 19, and 20 mm, respectively. The in vivo results indicated that the fermentation supernatant resulted in a high diarrhea inhibition rate (56%, p < 0.05), greatly enhanced the disruption of bacterial diversity caused by antibiotics, and restored the dominant position of L. johnsonii in the treatment and recovery stages. Therefore, the combination of the herb residue and probiotics suggests a potential to explore conversion of these materials for the possible development of therapies for AAD.

Deep eutectic solvents from hemicellulose-derived acids for the cellulosic ethanol refining of Akebia' herbal residues

Here, the potential use of herbal residues of Akebia as feedstock for ethanol production is evaluated. Additionally, five deep eutectic solvents from hemicellulose-derived acids were prepared to overcome biomass recalcitrance. Reaction temperatures had more significant influences on solid loss and chemical composition than the molar ratios of choline chloride (ChCl) to derived acids. Glycolic acid resulted in the maximum levels of lignin, xylan and glucan removal, which were 60.0%, 100% and 71.5%, respectively, at 120°C with a 1:6M ratio of ChCl-glycolic acid. In contrast, ChCl-formic acid resulted in the greatest level of glucan retention, at 97.8%, with a lignin removal rate of 40.7% under the same pretreatment conditions. Moreover, ChCl loading could significantly enhance the selectivity of carboxylic acid for lignin dissolution. A 98.0% level of subsequent enzymatic saccharification and a 100% ethanol yield were achieved after ChCl-formic acid pretreatments of Akebia' herbal residues.