Cellulose and hemicellulose (mostly xylan), together with lignin, are the major polymeric constituents of plant cell walls and from the largest reservoir of fixed carbon in nature. The enzymatic hydrolysis of polymeri...Cellulose and hemicellulose (mostly xylan), together with lignin, are the major polymeric constituents of plant cell walls and from the largest reservoir of fixed carbon in nature. The enzymatic hydrolysis of polymeric substances by extracellular enzymes, such as cellulases, hemicellulases and laccases, is preferred to chemical depolymerisation to avoid the production of toxic by-products and waste that are expensive to treat. The monosaccharides released through enzymatic hydrolysis can subsequently be microbially converted to commercial commodities, such as bio-ethanol (fuel extender) or microbial protein as feed supplements. The individual depolymerisering enzymes used, such as cellulases, xylanases and laccases, also have industrial application in (i) biobleaching in the paper and pulp industry, (ii) improvement of animal feed (poultry and ruminants) digestibility in feed industries, and (iii) dough rheology and bread volume in the baking process, and beer viscosity and filtration velocity during brewing. The cloning of the genes, coding for several xylan degrading enzymes, and their expression in Baker’s yeast (Saccharomyces cerevisiae) and filamentous fungi (Aspergillus species) opened the possibility to study the pure enzymes, without contaminating activity. Trichoderma reesei produces several of these enzymes and detailed information on their specificity, synergies and structure/activity relationships is known. An overview will be presented.展开更多
无论是现代环境治理体系抑或基层环境保护工作,均强调要广泛吸纳多方力量构建多元共治格局。立足自身方能展望未来,该研究以中国环境政策协同为切入点,围绕协同现状、短板剖析以及提升策略展开。评估环境政策协同的前提是环境政策的捕...无论是现代环境治理体系抑或基层环境保护工作,均强调要广泛吸纳多方力量构建多元共治格局。立足自身方能展望未来,该研究以中国环境政策协同为切入点,围绕协同现状、短板剖析以及提升策略展开。评估环境政策协同的前提是环境政策的捕获与协同要素的识别,故运用文本挖掘技术与“结构-过程”框架,为政策评估工作做前置准备。构建的环境政策数据池囊括1980—2022年共计871条政策,初步分解环境政策特质并抽离出效力位阶、时间间隔、发文机构和政策内容的标签信息。基于经济合作与发展组织(Organization for Economic Co‑operation and Development,OECD)提出的“结构-过程”协同框架,贴合环境政策领域做出框架调试,形成由要素、层级与区域构成的结构性机制和生效、执行与参与构成的过程性机制。政策量化结果显示:环境政策中要素协同未与环境特性紧密结合,层级协同的路径依赖严重,区域协同依靠具象化的环境纽带,时间协同缺乏机制性保障,工具协同“重管制、轻激励”,主体协同形式依赖地方探索。在时间序列下观察环境政策的协同变化,发现结构性机制式微,并实现由单维引领向多维互动的转变。这意味着,为提升环境政策协同效果,在结构性机制中应加强对环境特性的关注,推动精细化管理;优化垂直管理层级结构,畅通双向信息通道;加强内生性价值观念的培养,减少对具象化环境纽带的依赖。在过程性机制中将时间纳入政策制定的考虑范围,进行科学的计划和安排;融合刚性环境规制与柔性激励工具,实现更加灵活和有效的政策运用;同时,加强环境多元共治的社会结构建设,确保地方探索成功实施。展开更多
文摘Cellulose and hemicellulose (mostly xylan), together with lignin, are the major polymeric constituents of plant cell walls and from the largest reservoir of fixed carbon in nature. The enzymatic hydrolysis of polymeric substances by extracellular enzymes, such as cellulases, hemicellulases and laccases, is preferred to chemical depolymerisation to avoid the production of toxic by-products and waste that are expensive to treat. The monosaccharides released through enzymatic hydrolysis can subsequently be microbially converted to commercial commodities, such as bio-ethanol (fuel extender) or microbial protein as feed supplements. The individual depolymerisering enzymes used, such as cellulases, xylanases and laccases, also have industrial application in (i) biobleaching in the paper and pulp industry, (ii) improvement of animal feed (poultry and ruminants) digestibility in feed industries, and (iii) dough rheology and bread volume in the baking process, and beer viscosity and filtration velocity during brewing. The cloning of the genes, coding for several xylan degrading enzymes, and their expression in Baker’s yeast (Saccharomyces cerevisiae) and filamentous fungi (Aspergillus species) opened the possibility to study the pure enzymes, without contaminating activity. Trichoderma reesei produces several of these enzymes and detailed information on their specificity, synergies and structure/activity relationships is known. An overview will be presented.
文摘无论是现代环境治理体系抑或基层环境保护工作,均强调要广泛吸纳多方力量构建多元共治格局。立足自身方能展望未来,该研究以中国环境政策协同为切入点,围绕协同现状、短板剖析以及提升策略展开。评估环境政策协同的前提是环境政策的捕获与协同要素的识别,故运用文本挖掘技术与“结构-过程”框架,为政策评估工作做前置准备。构建的环境政策数据池囊括1980—2022年共计871条政策,初步分解环境政策特质并抽离出效力位阶、时间间隔、发文机构和政策内容的标签信息。基于经济合作与发展组织(Organization for Economic Co‑operation and Development,OECD)提出的“结构-过程”协同框架,贴合环境政策领域做出框架调试,形成由要素、层级与区域构成的结构性机制和生效、执行与参与构成的过程性机制。政策量化结果显示:环境政策中要素协同未与环境特性紧密结合,层级协同的路径依赖严重,区域协同依靠具象化的环境纽带,时间协同缺乏机制性保障,工具协同“重管制、轻激励”,主体协同形式依赖地方探索。在时间序列下观察环境政策的协同变化,发现结构性机制式微,并实现由单维引领向多维互动的转变。这意味着,为提升环境政策协同效果,在结构性机制中应加强对环境特性的关注,推动精细化管理;优化垂直管理层级结构,畅通双向信息通道;加强内生性价值观念的培养,减少对具象化环境纽带的依赖。在过程性机制中将时间纳入政策制定的考虑范围,进行科学的计划和安排;融合刚性环境规制与柔性激励工具,实现更加灵活和有效的政策运用;同时,加强环境多元共治的社会结构建设,确保地方探索成功实施。
