[Analysis of the epidemiological characteristics of scarlet fever in Yantai City, Shandong Province from 2015 to 2019].

From 2015 to 2019, the annual average incidence rate of scarlet fever was 7.80/100 000 in Yantai City, which showed an increasing trend since 2017 (χ2trend=233.59, P<0.001). The peak period of this disease was from April to July and November to January of the next year. The ratio of male to female was 1.49∶1, with a higher prevalence among cases aged 3 to 9 years (2 357/2 552, 92.36%). Children in kindergartens, primary and middle school students, and scattered children were the high risk population, with the incidence rate of 159.86/100 000, 25.57/100 000 and 26.77/100 000, respectively. The global spatial auto-correlation analysis showed that the global Moran's I index of the reported incidence rate of scarlet fever in Yantai from 2015 to 2019 was 0.28, 0.29, 0.44, 0.48, and 0.22, respectively (all P values<0.05), suggesting that the incidence rate of scarlet fever in Yantai from 2015 to 2019 was spatial clustering. The local spatial auto-correlation analysis showed that the "high-high" clustering areas were mainly located in Laizhou City, Zhifu District, Haiyang City, Fushan District and Kaifa District, while the "low-high" clustering areas were mainly located in Haiyang City and Fushan District.

[Enlightening from optimizing post-authorization safety monitoring system of SARS-CoV-2 vaccines in major economies worldwide].

Ongoing global pandemic of Coronavirus Disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has promoted the unprecedented rapid development and large-scale rolling out of different platform-based COVID-19 vaccines worldwide. How to effectively respond to the expected scale increasing adverse events after vaccination campaign of COVID-19 vaccines is a common problem faced by the world. A lot of countries and regions around the world have arranged in advance at different levels, optimizing the original vaccine safety monitoring system from the perspectives of strengthening the foundation and capabilities, promoting internal and external cooperation, upgrading methods, as well as improving transparency and public communication, which has ensured the good and efficient operation of the system and can provide reference for the construction of relevant fields in China.

[The surveillance analysis of the adverse events following immunization of the domestic 13-valent pneumococcal polysaccharide conjugate vaccine in Zhejiang Province].

To evaluate the safety of the domestic 13-valent pneumococcal polysaccharide conjugate vaccine-tetanus toxoid protein (PCV13-TT) after its licensure. The adverse event following immunization (AEFI) and the vaccination data of PCV13-TT in Zhejiang province from July 2020 to October 2021 were collected from national adverse event following immunization surveillance system and Zhejiang provincial immunization information system. Descriptive epidemiological method was used for this analysis. From July 2020 to October 2021, 302 317 doses of PCV13-TT were administered in children under 6 years old in Zhejiang Province and 636 AEFI case reports were received, with a reporting rate of 21.04 per 10 000 doses. Of these AEFI cases, 97.17% were mild vaccine product-related reaction (20.54 per 10 000 doses) and 95.44% occurred in the 0-1 d after vaccination (20.08 per 10 000 doses). The most common clinical diagnoses of AEFI included fever (224 cases), redness (204 cases), and induration (190 cases), while allergic rash (11 cases) was the most common diagnosis among the abnormal reactions. In conclusion,the present results bolstered that the domestic PCV13-TT was generally well tolerated in children under 6 years old in Zhejiang Province.

[An exploratory framework of vaccine hesitancy monitoring and early warning system in China].

Vaccine hesitancy has spread worldwide recent years and resulting in increasing incidence of some well-controlled vaccine-preventable diseases, which is extremely unfavorable to the consolidation of the national immunization programme and the elimination of corresponding diseases. Based on the Complacency, Convenience and Confidence ("3Cs") model of vaccine hesitancy, combined with the practice experience of management of quality control through the whole vaccine life cycle in China, we introduce a framework of vaccine hesitancy monitoring and early warning in China to provide a reference for carrying out corresponding work. The indicator system of the framework derives from monitoring of vaccine life cycle quality management, population vaccine confidence, and service availability.

[A case of subacute combined degeneration of spinal cord caused by inhaling laughing gas].

Laughing gas (Nitrogen monoxide) is currently abused due to its low price and easy availability. This article discussed the clinical manifestations of a patient with subacute combined degeneration of the spinal cord caused by inhalation of laughing gas. The patient developed numbness of extremities, unstable walking, and decreased serum vitamin B(12) level. MRI of the cervical spine showed abnormal signals in the lateral and posterior cords of the cervical spinal cord (C2-6) , neuroelectrophysiological examination showed peripheral nerve damage in the extremities. After treatment with vitamin B(12) supplementation, the patient's condition gradually improved. Clinicians diagnose subacute combined degeneration of the spinal cord, especially when the patient has no gastrointestinal disease, diet, malnutrition, etc., they need to carefully inquire about the history of nitrous oxide inhalation to avoid missed diagnosis.

[Post-marketing observation on safety of inactivated enterovirus A71 vaccine (human diploid cell)].

Objective: To evaluate the post-marketing safety of inactivated Enterovirus type 71 (EV-A71) vaccine (human diploid cell) . Methods: A total of 20 191 healthy children aged 6 to 59 months were invited to receive 2 doses of EV-A71 vaccine in Zhejiang Province from September 2016 to December 2017. Child caregivers were followed up on the 4(th) or 5(th) day after each EV-A71 vaccination, and the incidence of local, systemic, and other adverse events within 3 days after vaccination was recorded to assess vaccine safety. Describe the differences in adverse events among children with different characteristics. Results: A total of 32 230 doses were observed in this study, of which 20 191 and 12 039 were vaccinated for the first and the second dose, respectively; and the incidence of adverse events within 3 days was 2.045% (413 doses) and 1.611% (194 doses), respectively. After the first and the second dose, the number of systemic adverse events was the highest, 371 and 175 cases, respectively, with an incidence of 1.837% and 1.454%, respectively; the number of local adverse events was the lowest, 14 and 2 doses, respectively, with an incidence of 0.069% and 0.017%. Local adverse events occurred after vaccination were generally mild, and only 2 patients had level of 3; among the systemic adverse events, 39 patients had a fever level of 3 or higher, accounting for 8.2% of the total fever. Most of the symptoms in the local adverse events did not require treatment, only 3 cases of vaccination site rash and 2 cases of pruritus were self-purchased drugs or outpatient treatment; except for 5 cases of fever, the other symptoms were not hospitalized in the case of systemic adverse events. Conclusion: The incidence of adverse events within 3 days after vaccination with EV-A71 vaccine was low in children, mainly systemic adverse events, and the prognosis was good.

[Post-marketing safety analysis of inactivated enterovirus A71 vaccines].

Objectives: To evaluate the safety of inactivated enterovirus A71(EV-A71) vaccines after large-scale immunization in the community. Methods: We selected EV-A71 susceptible people (healthy children) aged 6-59 months in vaccination clinics from 89 counties in Zhejiang Province between April 2016 and March 2018. All local and systematic adverse actions were collected by 30 min on-site inspection, within 3 days and 4-30 days follow-up. Chi-square test and Fisher's exact test were used to compare the difference of AEs incidence in various characteristics among two groups. Results: A total of 71 663 doses of vaccines were included for active safety analysis, which included 37 331 doses in boys and 34 332 doses in girls. Among all the doses, children aged 6 to 11 months, 12 to 23 months and 24 to 59 months were received 13 707, 32 639 and 25 317 doses respectively. The incidence of adverse reactions within 30 min, 3 days and 4-30 days were 0.33% (239 doses), 1.58% (1 133 doses) and 0.34% (244 doses) respectively. Adverse reactions within 3 days were 1 372 doses, with a incidence of 1.91%; among all the cases, 539 doses (0.75%) were grade 1, 677 doses (0.94%) were grade 2 and 156 doses (0.22%) were grade 3, no grade-4 adverse reaction was reported. The common local adverse reactions were redness, swelling and pruritus, with the incidence rates were 0.05% (39 doses), 0.02% (16 doses) and 0.02% (12 doses), respectively, while the most common systemic adverse reaction was pyrexia with an incidence of 1.19% (856 doses), followed by diarrhea and anorexia with the incidence rates were 0.15% (104 doses) and 0.13% (90 doses) respectively. Conclusion: Most adverse actions of EV-A71 vaccines were mild and moderate and majority of them were common adverse actions. No new adverse reactions were found in the study.

Mental health and related influencing factors among the empty-nest elderly and the non-empty-nest elderly in Taiyuan, China: a cross-sectional study.

OBJECTIVE: In China, elderly make up a large proportion of the society, but their mental health is often overlooked. The aim of this study is to compare mental health and related influencing factors among the empty-nest and the non-empty-nest elderly, and attain the purpose of improving their quality of life. STUDY DESIGN: Cross-sectional survey. METHODS: A cross-sectional survey was conducted among 488 elderly people aged 60-92 years in six districts of Taiyuan, China. A demographic questionnaire and SCL-90-R were employed to collect demographic variables and evaluate mental health, respectively. Multiple regression analysis was performed to estimate factors related to mental health of the elderly. RESULTS: The empty-nest elderly were mostly male, married, higher education level, higher income and living in urban areas. The scores of SCL-90-R among the empty-nest elderly were lower than those of the non-empty-nest elderly except for psychoticism. Comparing with scores of national norms, some dimension of SCL-90-R had statistically significant differences. Multiple regression analysis showed that the main risk factors of the empty-nest elderly were gender and income, whereas the main risk factor of the non-empty-nest elderly was chronic diseases. CONCLUSION: The mental health status of the empty-nest elderly was better than that of the non-empty-nest elderly. Overall mental health of the study population was at a high level compared with national norms. The elderly who were male, with younger age, having higher income, and without chronic diseases had better mental health status.

Survey of attitude and knowledge of reproductive health among middle school students in Luoyang, China.

The aim of this study was to assess the knowledge and attitude of AIDS and sexual behavior of middle school students. Structural questionnaires were designed to interview 1980 junior and senior middle school students about their basic knowledge, attitude, and behavior with respect to AIDS and sexual behavior. Students were recruited from the six most common middle schools of the six regions in Luoyang City of the Henan Province of China by cluster sampling from September to December of 2004. Results showed that 54.5% of students had not learned about the prevention of HIV/AIDS in school, and 38.3% of students did not have any knowledge about the route of transmission of HIV/AIDS. Furthermore, 91.2% of students were reluctant to share a classroom with HIV/AIDS patients. Approximately 21.7% of students had read books, watched videos, and consulted other media related to sex, 1.1% of students had had sexual intercourse during high school, and 80.5% believed that health education on HIV/AIDS and sex was necessary. The results of this survey showed that middle school students have little knowledge about HIV/AIDS and sex. Therefore, health education programs for HIV/AIDS prevention and sexual health should be developed as soon as possible to help students peacefully get through a sexually puzzling period of life.

Mesoporous cellulose-chitosan composite hydrogel fabricated via the co-dissolution-regeneration process as biosorbent of heavy metals.

Developing low-cost and high-performance biosorbent for water purification continues drawing more and more attention. In this study, cellulose-chitosan composite hydrogels were fabricated via a co-dissolution and regeneration process using a molten salt hydrate (a 60 wt% aqueous solution of LiBr) as a solvent. The addition of chitosan not only introduced functionality for metal adsorption but also increased the specific surface area and improved the mechanical strength of the composite hydrogel, compared to pure cellulose hydrogel. Batch adsorption experiments indicated that the composite hydrogel with 37% cellulose and 63% chitosan exhibited an adsorption capacity of 94.3 mg/g (1.49 mmol/g) toward Cu2+ at 23 °C, pH 5, and initial metal concentration of 1500 mg/L, which was 10 times greater than the adsorption capacity of pure cellulose hydrogel. Competitive adsorption from a mixed metals solution revealed that the cellulose-chitosan composite hydrogel exhibited selective adsorption of the metals in the order of Cu2+ > Zn2+ > Co2+. This study successfully demonstrated an innovative method to fabricate biosorbents from abundant and renewable natural polymers (cellulose and chitosan) for removing metal ions from water.

Ethanol production from SPORL-pretreated lodgepole pine: preliminary evaluation of mass balance and process energy efficiency.

Lodgepole pine from forest thinnings is a potential feedstock for ethanol production. In this study, lodgepole pine was converted to ethanol with a yield of 276 L per metric ton of wood or 72% of theoretical yield. The lodgepole pine chips were directly subjected to sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) pretreatment and then disk-milled; the recovered cellulose substrate was quais-simultaneously saccharified enzymatically and fermented to ethanol using commercial cellulases and Saccharomyces cerevisiae D5A. The liquor stream from the pretreatment containing hydrolyzed sugars mainly from hemicelluloses was fermented by the same yeast strain after detoxification using an XAD resin column. The SPORL pretreatment was conducted at 180 degrees C for a period of 25 min with a liquor-to-wood ratio of 3:1 (v/w) in a laboratory digester. Three levels of sulfuric acid charge (0.0%, 1.4%, and 2.2% on an oven dried wood basis in w/w) and three levels of sodium bisulfite charge (0.0%, 4.0%, and 8.0% in w/w) were applied. Mechanical and thermal energy consumption for milling and pretreatment were determined. These data were used to determine the efficiency of sugar recoveries and net ethanol energy production values and to formulate a preliminary mass and energy balance.

Methionine and selenium yeast supplementation of the maternal diets affects antioxidant activity of breeding eggs.

Four hundred fifty 52-wk-old Langshan layer hens (dual-purpose type, an indigenous poultry breed of China) were randomly divided into 9 treatments with 5 replicates in each treatment. Birds were fed corn-soybean diets (0.13 mg of Se/kg) supplemented with 0, 0.30, and 0.60 mg/kg of Se from Se yeast and 3.2, 4.0, and 5.4 g of dl-Met/kg, respectively. Increasing Se yeast supplementation significantly increased Se concentration in the egg yolk (P < 0.01) and the Se concentration of the 3.2 g of Met/kg treatment was higher than those of the 4.0 and 5.4 g of Met/kg treatments. Adding 0.3 mg of Se/kg to the diet significantly increased glutathione peroxidase (GSH-Px) activity in the egg yolk compared with 0 and 0.6 mg of Se/kg (P < 0.01) and increasing Se yeast supplementation significantly increased the GSH-Px activity in the egg albumen (P < 0.01). Increasing Met supplementation significantly decreased the GSH-Px activity in both the yolk and the albumen of the eggs (P < 0.01). Methionine supplemented at 3.2 and 4.0 g/kg significantly increased glutathione concentration in the egg yolk compared with 5.4 g of Met/kg (P < 0.01) and increasing Met supplementation increased the glutathione concentration in the egg albumen. Increasing Met supplementation significantly decreased malondialdehyde concentration in the egg yolk (P < 0.01) and Se supplemented at 0 and 0.6 mg/kg increased the malondialdehyde concentrations in the egg yolk compared with 0.3 mg of Se/kg (P < 0.01). Methionine supplemented at 4.0 and 5.4 g/kg significantly decreased carbonyl concentration compared with 3.2 g of Met/kg. The conclusion was drawn that Se yeast and Met supplementation of the maternal diets could enhance antioxidant activity of breeding eggs.

Effects of heat exposure on muscle oxidation and protein functionalities of pectoralis majors in broilers.

This study was conducted to determine the effects of heat stress on pH, lipid peroxidation, protein oxidation, and functionalities of breast meat in broilers. The experimental birds were exposed to 2 temperatures: 24 degrees C (control) and 41 degrees C (heat-stressed) for 0, 1, 2, 3, and 5 h. As compared with control, the pH determinations after slaughter for 30 min and 24 h of chilling, respectively, of the pectoralis major in the heat-stressed groups were significantly lower (P < 0.05). Oxidative stability of i.m. lipid in 3- and 5-h groups (P < 0.01) and protein in 2-, 3-, and 5-h groups (P < 0.01) increased. Protein solubility of pectorilas major decreased after heat exposure. Drip loss and cooking loss were increased in groups from 1 to 5 h of exposure. A reduced strength was noted for myofibrillar protein gels of heat-stressed breasts in exposed groups (P < 0.01); also water-holding capacity of the gels was reduced in treatments of 2, 3, and 5 h (P < 0.01). The results demonstrated that preslaughter exposures to heat reduced the oxidative stability of broiler muscle protein, which might be responsible for decreased protein functionalities such as gelation.

Methionine and selenium yeast supplementation of the maternal diets affects color, water-holding capacity, and oxidative stability of their male offspring meat at the early stage.

Four hundred fifty 52-wk-old Lang-shan breeding hens (dual-purpose type, an indigenous poultry breed of China) were randomly divided into 9 treatments with 5 replicates each treatment. They were fed corn-soybean diets with 0, 0.30, and 0.60 mg of Se/kg from Se yeast and 3.2, 4.0, and 5.4 g of dl-Met/kg, respectively. After incubation, 250 chickens each treatment were randomly divided into 5 replicates and fed the same diet. At 21 d old, 10 male chicks in each treatment were slaughtered. There results were as follows. (1) The Se content significantly increased with the increase of Se yeast supplementation (P < 0.01). (2) The carbonyl content of the myofibrillar protein significantly decreased with the increase of Met supplementation (P < 0.01) and the carbonyl content of the 0 mg of Se/kg treatment was higher than the 0.3 mg of Se/kg treatment (P < 0.01). (3) Selenium supplementation at 0.30 and 0.60 mg/kg significantly decreased malondialdehyde content compared with that of 0 mg of Se/kg (P < 0.01) and 4.0 and 5.4 g of Met/kg supplementation significantly decreased malondialdehyde content compared with that of 3.2 g of Met/kg (P < 0.01). (4) Supplementation of Met at 5.4 g/kg significantly increased International Commission on Illumination a* value compared with 3.2 and 4.0 g of Met/kg (P < 0.01). Supplementation of Se at 0.6 mg/kg significantly increased a* value compared 0 and 0.3 mg of Se/kg (P < 0.01) and 0 mg of Se/kg significantly increased b* value compared with 0.30 and 0.60 mg of Se/kg (P < 0.01). (5) Selenium supplemented at 0.30 and 0.60 mg/kg decreased drip loss compared with 0 mg of Se/kg and 4.0 and 5.4 g of Met/kg decreased drip loss compared with 3.2 g of Met/kg, respectively. The conclusion was drawn that Met and Se yeast supplementation of the maternal diets could improve color, water-holding capacity, and oxidative stability of male offspring meat to an extent.

Effect of alkali metal cation on the anaerobic hydrolysis and acidogenesis of vegetable waste.

Five batch testing scenarios were designed to evaluate the effects of alkali metal cations on anaerobic hydrolysis and acidogenesis. These scenarios were A (c=0 g l(-1)), B (cNa+=25 g l(-1)), C (cNa+=50 g l(-1)), D (cK+=25 g l(-1)), and E (cK+=50 g l(-1), pH 7.0). A solution pH of 7.0 or above favored protein hydrolysis, higher proteinase activity and higher ammonia production. However, such a pH suppressed carbohydrate hydrolysis, as indicated by low alpha-amylase activity. Cation interference at pH 5.0-6.0 seemed not to affect carbohydrate hydrolysis, as showed by the unimpaired alpha-amylase activity at 50 g l(-1) K+. Acidogenesis was more sensitive to alkali metal cations, so acid production and the drop in pH were lowest in a 25-50 g l(-1) Na+, acidic environment (pH 4.0-6.0). It was insensitive to cations when the pH was maintained at 7.0-8.0. When the pH was uncontrolled and decreased freely to acidic values, 25 g l(-1) of cation inhibited the action of the microbes, which rapidly acclimated, as presented by the slow transformation of soluble polymers to soluble metabolites. However, acidogenetic microbes could not easily recover from inhibition by 50 g l(-1) of cation. When the pH was maintained at over 7.0, the microbes were not inhibited by cation (50 g l(-1)) as indicated by the more active acidogenesis. The metabolic pathways to lactate, acetate and alcohols were not fully coupled.

Sulfite (SPORL) pretreatment of switchgrass for enzymatic saccharification.

SPORL (Sulfite Pretreatment to Overcome Recalcitrance of Lignocellulose) pretreatment was applied to switchgrass and optimized through an experimental design using Response Surface Methodology within the range of temperature (163-197 °C), time (3-37 min), sulfuric acid dosage (0.8-4.2% on switchgrass), and sodium sulfite dosage (0.6-7.4% on switchgrass). Performance of SPORL was compared with that of dilute acid (DA) and alkali (AL) in switchgrass pretreatment. Results indicated that SPORL pretreatment improved the digestibility of switchgrass through sufficiently removing hemicellulose, partially dissolving lignin, and reducing hydrophobicity of lignin by sulfonation. The removal of hemicellulose was more critical to substrate digestibility than the removal of lignin during SPORL pretreatment. SPORL pretreated switchgrass had better enzymatic digestibility than DA and AL pretreated ones. The SPORL pretreated switchgrass could be hydrolyzed by 83% within 48 h with 15 FPU (filter paper unit) cellulase and 30 CBU (cellobiose unit) ß-glucosidase/g cellulose.

Sleeping Beauty transposon system is a reliable gene delivery tool for hereditary tyrosinaemia type 1 disease gene therapy: size of the foreign gene decides the timing of stable integration into the host chromosomes.

OBJECTIVE: This study investigated compensation for loss of the fumaryl-acetoacetate hydrolase gene (Fah) by gene therapy using the Sleeping Beauty transposon system (SBTS), in a hereditary tyrosinaemia type 1 (HT-1) mouse model (Fah-/-). METHODS: Twenty Fah-/- study mice, five wild-type positive controls and five Fah-/- negative controls were included. All Fah-/- mice received 2-(2-nitro-4-trifluoro-methylbenzoyl)-1,3-cyclo hexaedione (NTBC). Fah-/- study mice were randomly injected with one of two SBTS constructs: Fah-SBTS (containing mouse Fah gene), or forkhead box M1b (FOXM1B)-Fah-SBTS (containing mouse Fah and human FOXM1B genes). Firefly luciferase-SBTS was injected as a trace marker. NTBC treatment stopped after construct injection; Fah-/- negative controls were kept healthy with continued NTBC. Mice were weighed daily; the luciferase signal was monitored by in vivo bioluminescence, and Fah and FOXM1B gene expression were evaluated. RESULTS: The Fah gene integrated into the mouse chromosomes within 1 week of Fah-SBTS injection (mice survived without NTBC thereafter) and within 1 month of FOXM1B-Fah-SBTS injection (mice lost weight dramatically and needed additional NTBC). CONCLUSION: The shorter Fah gene had an advantage over the longer FOXM1B-Fah gene for stable integration into the host mouse chromosomes.

Comparisons of SPORL and dilute acid pretreatments for sugar and ethanol productions from aspen.

This study reports comparative evaluations of sugar and ethanol production from a native aspen (Populus tremuloides) between sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) and dilute acid (DA) pretreatments. All aqueous pretreatments were carried out in a laboratory wood pulping digester using wood chips at 170°C with a liquid to oven dry (od) wood ratio (L/W) of 3:1 at two levels of acid charge on wood of 0.56 and 1.11%. Sodium bisulfite charge on od wood was 0 for DA and 1.5 or 3.0% for SPORL. All substrates produced by both pretreatments (except DA with pretreatment duration of 0) had good enzymatic digestibility of over 80%. However, SPORL produced higher enzymatic digestibility than its corresponding DA pretreatment for all the experiments conducted. As a result, SPORL produced higher ethanol yield from simultaneous saccharification and fermentation of cellulosic substrate than its corresponding DA pretreatment. SPORL was more effective than its corresponding DA pretreatment in reducing energy consumption for postpretreatment wood chip size-reduction. SPORL, with lower energy input and higher sugar and ethanol yield, produced higher sugar and ethanol production energy efficiencies than the corresponding DA pretreatment.

Woody biomass pretreatment for cellulosic ethanol production: Technology and energy consumption evaluation.

This review presents a comprehensive discussion of the key technical issues in woody biomass pretreatment: barriers to efficient cellulose saccharification, pretreatment energy consumption, in particular energy consumed for wood-size reduction, and criteria to evaluate the performance of a pretreatment. A post-chemical pretreatment size-reduction approach is proposed to significantly reduce mechanical energy consumption. Because the ultimate goal of biofuel production is net energy output, a concept of pretreatment energy efficiency (kg/MJ) based on the total sugar recovery (kg/kg wood) divided by the energy consumption in pretreatment (MJ/kg wood) is defined. It is then used to evaluate the performances of three of the most promising pretreatment technologies: steam explosion, organosolv, and sulfite pretreatment to overcome lignocelluloses recalcitrance (SPORL) for softwood pretreatment. The present study found that SPORL is the most efficient process and produced highest sugar yield. Other important issues, such as the effects of lignin on substrate saccharification and the effects of pretreatment on high-value lignin utilization in woody biomass pretreatment, are also discussed.

On energy consumption for size-reduction and yields from subsequent enzymatic saccharification of pretreated lodgepole pine.

This study investigated the effects of chemical pretreatment and disk-milling conditions on energy consumption for size-reduction and the efficiency of enzymatic cellulose saccharification of a softwood. Lodgepole pine wood chips produced from thinnings of a 100-year-old unmanaged forest were pretreated by hot-water, dilute-acid, and two SPORL processes (Sulfite Pretreatment to Overcome Recalcitrance of Lignocellulose) at acid charge on oven dry (od) wood of 0% and 2.21%. The pretreated wood chips were then milled using a laboratory disk mill under various solids-loadings and disk-plate gaps to produce substrates for enzymatic hydrolysis. We found that post-chemical-pretreatment size-reduction of forest biomass can decrease size-reduction energy consumption by 20-80% depending on the pretreatment applied under 20% solids-loading and a disk-plate gap of 0.76 mm in milling. SPORL with a sodium bisulfite charge of 8% and sulfuric acid charge of 2.21% on wood was the most effective in decreasing size-reduction energy consumption. Solids-loading had the most significant effect on disk-milling energy. When solids-loading was reduced from 30% to 3%, disk-milling energy could be decreased by more than a factor of 10 for wood chips pretreated by both SPORL and dilute-acid at an acid charge of 2.21%. The enzymatic hydrolysis glucose yields (EHGY) from the substrates produced by all pretreatments were independent of the solids-loading in milling, indicating that these energy savings in size-reduction can be realized without affecting EHGY. When wood chips were pretreated by SPORL with 2.21% acid charge, size-reduction energy consumption was decreased to less than 50 Wh/kg od wood at a practical solids-loading of approximately 10-20%, equivalent to that used in size-reduction of agriculture biomass, with excellent EHGY of about 370 g per kg od wood. Similar effects on size-reduction energy savings and excellent EHGY were also achieved when large disk-plate gaps (up to 1.52 mm studied) were applied in disk-milling of wood chips pretreated by SPORL with acid.