Initiating aerobic fermentation under low temperature is the main challenge for winter livestock manure composting. This study aims to address this issue by applying black soldier fly larvae (BSFL) frass as a co-composting additive to enhance the low-temperature composting process. Specifically, this work explored the effects of chicken manure and BSFL frass co-composting on the temperature, humus content, and microorganisms with fresh weight ratio of 2:1, 1:1, 1:2 (w/w) at 6 degrees C. The result showed frass could rapidly rise the temperature to 50 degrees C and significantly increased the humus content by 15.6 % similar to 26.3 %. Moreover, microbial analysis revealed that Sphingobacteriaceae accelerated temperature rise via low-temperature reproduction, creating proper temperature for thermophilic bacteria (Truepera and Georgia). Additionally, Cellulomonas and other bacteria promoted organic matter degradation and participated in humus formation. This study presents a novel solution for low-temperature composting, providing practical insights for improving manure management in winter.

Nanobubble water promotes the degradation of difficult-to-degrade organic matter, improves the activity of electron transfer systems during anaerobic digestion, and optimizes the composition of anaerobic microbial communities. Therefore, this study proposes the use of nanobubble water to improve the yield of medium chain carboxylic acids produced from cow manure by chain elongation. The experiment was divided into two stages: the first stage involved the acidification of cow manure to produce volatile acidic fatty acids as electron acceptors, and the second phase involved the addition of lactic acid as an electron donor for the chain elongation. Three experimental groups were established, and air, H2, and N2 nanobubble water were added in the second stage. Equal amounts of deionized water were added in the control group. The results showed that nanobubble water supplemented with air significantly increased the caproic acid concentration to 15.10 g/L, which was 55.03 % greater than that of the control group. The relative abundances of Bacillus and Caproiciproducens, which are involved in chain elongation, and Syntrophomonas, which is involved in electron transfer, increased. The unique ability of air nanobubble water supplemented to break down the cellulose matrix resulted in further decomposition of the recalcitrant material in cow manure. This effect subsequently increased the number of microorganisms associated with lignocellulose degradation, increasing carbohydrate metabolism and ATPbinding cassette transporter protein activity and enhancing fatty acid cycling pathways during chain elongation. Ultimately, this approach enabled the efficient production of medium chain carboxylic acids.

黑水虻Hermetia illucens作为一种新型资源环境昆虫,其幼虫可以处理餐厨垃圾、畜禽粪便、蔬菜残体等各种有机废弃物.幼虫富含蛋白质和油脂,可以作为水产饲料的蛋白来源.本研究探索黑水虻幼虫处理餐厨垃圾过程中其养分组成与消化酶活性变化之间的关系.通过黑水虻幼虫自由取食餐厨垃圾,每日采集样品用于物质养分和消化酶活性的测定.结果显示:黑水虻幼虫粗蛋白含量呈现先下降后上升的变化规律,而幼虫总糖含量呈现先上升后下降的变化规律,粗脂肪含量维持上升的趋势.幼虫处理餐厨垃圾过程中,体内蛋白酶在初期迅速上升,第6天后逐渐下降,而淀粉酶呈现出先缓慢上升再迅速上升最后下降的变化规律.脂肪酶在黑水虻幼虫处理餐厨垃圾前期保持较高的活性然后缓慢下降.同时,通过相关性分析,黑水虻幼虫粗蛋白含量变化与蛋白酶活性没有相关性,而总糖与粗脂肪含量变化分别与淀粉酶、脂肪酶有相关性.因此,部分消化酶活性变化与黑水虻幼虫养分组成具有一定的联系,本研究结果为工厂化养殖黑水虻提供一定的理论基础.

以获得黑水虻Hermetia illucens转化有机废弃物的养殖投喂工艺参数为目标,采用实验室小试模拟试验,以餐厨垃圾为试验原料,研究不同投料方式(1次、2次、3次和4次投料)对黑水虻转化餐厨垃圾过程中幼虫生长性能的影响.结果表明,采用多次投料方式,随着投料次数增加,对转化物料料温波动影响较大,不利于幼虫快速生长;在投虫量和投料量相同条件下,养殖周期为10 d,其中以1次投料处理组的收虫体重、体长、单位面积虫产量为最高,料虫比为最低,与2次投料差异不显著(P>0.05),但与3次、4次投料处理组差异显著(P<0.05);黑水虻转化废弃物前期较低的物料含水率更加有利于虫体生长,而后期物料含水率较高则更为有利.通过生产性能分析发现,从投料回报效果角度考虑生产性能以1次投料为最佳,而从高效率处理餐厨垃圾和投料回报效果两者角度综合分析,生产性能以2次投料为最佳.该结果可为构建黑水虻转化餐厨垃圾标准化生产工艺参数技术体系奠定基础.

畜禽养殖业是农业碳排放的重要来源,也是气候变化的重要贡献者.为了量化畜禽养殖业的碳排放,为畜禽养殖业的碳减排提供依据,寻找合适的畜禽养殖业碳排放计算方法成为目前的研究热点.从碳排放到碳足迹,国内外畜禽养殖业的碳排放计算方法正朝着全面化和完整化的方向发展.参考国内外有关畜禽养殖业碳排放的相关文献,介绍OECD(经济合作与发展组织)法、IPCC(联合国政府间气候变化专门委员会)系数法、质量平衡法3种畜牧养殖业碳排放的计算方法及投入产出法、生命周期评价法2种碳足迹计算方法.在3种碳排放方法中,IPCC系数法相较于OECD法具有更全面且准确的优势,而IPCC系数法在计算排放设备更换频繁、自然排放源复杂的情况下没有质量平衡法准确.研究发现,在2种碳足迹的计算方法中,基于过程的生命周期评价法是目前计算碳足迹的主流方法,该方法体现了较高的系统性和完整性,适用于畜禽养殖业碳足迹的计算.