Gebiola Marco, Rodriguez Michael V, Garcia Alexandro, Garnica Andrea, Tomberlin Jeffery K, Hopkins Francesca M, Mauck Kerry E
Department of Entomology, University of California Riverside, Riverside, CA, USA.
Department of Environmental Sciences, University of California Riverside, Riverside, CA, USA.
Waste Manag. 2023 Sep 30;171:411-420. doi: 10.1016/j.wasman.2023.09.033.
Digestion of waste feedstocks by larvae of the black soldier fly Hermetia illucens (Diptera: Stratiomyidae) (BSF) results in proteins for animal feed and organic fertilizer with a reduced environmental footprint, but it can still have negative environmental effects through greenhouse gas (GHG) and ammonia (NH) emissions. Both biomass conversion by BSF larvae and associated GHG and NH emissions can depend on substrate properties that may be optimized through microbial inoculation pre-treatments, such as bokashi fermentation. Here, we quantified the effects of bokashi fermentation of brewery's spent grains on BSF rearing metrics and associated GHG and NH emissions at benchtop scale. We found that bokashi fermentation increased larval biomass by 40% and shortened development time by over two days on average, compared with unfermented spent grains. In line with increased larval growth, CO emissions in BSF larvae treatments were 31.0 and 79.0% higher in the bokashi fermented spent grains and Gainesville substrates, respectively, compared to the unfermented spent grains. Adding BSF larvae to the spent grains increased cumulative NO emissions up to 64.0 mg NO kg substrate but there were essentially no NO emissions when larvae were added to fermented spent grains. Bokashi fermentation also reduced NH fluxes from the volatilization of substrate nitrogen in the BSF larvae treatment by 83.7-85.8% during days 7 and 9, possibly by increasing N assimilation by larvae or by reducing the transformation of substrate NH to NH. Therefore, bokashi fermentation may be applied to improve performance of BSF larvae on a common industrial waste stream and reduce associated emissions.
黑水虻（双翅目：水虻科）幼虫对废弃原料的消化产生了用于动物饲料的蛋白质和环境足迹较小的有机肥料，但它仍可能通过温室气体（GHG）和氨（NH）排放产生负面环境影响。黑水虻幼虫的生物质转化以及相关的温室气体和氨排放都可能取决于底物特性，这些特性可以通过微生物接种预处理（如EM堆肥发酵）来优化。在这里，我们在实验室规模上量化了啤酒糟的EM堆肥发酵对黑水虻饲养指标以及相关温室气体和氨排放的影响。我们发现，与未发酵的啤酒糟相比，EM堆肥发酵使幼虫生物量增加了40%，平均发育时间缩短了两天多。与幼虫生长增加一致，在EM堆肥发酵的啤酒糟和盖恩斯维尔底物处理中，黑水虻幼虫的CO排放量分别比未发酵的啤酒糟高出31.0%和79.0%。向啤酒糟中添加黑水虻幼虫使累积NO排放量增加至64.0 mg NO kg底物，但当向发酵的啤酒糟中添加幼虫时，基本上没有NO排放。EM堆肥发酵还使黑水虻幼虫处理中第7天和第9天底物氮挥发产生的NH通量减少了83.7 - 85.8%，这可能是通过增加幼虫对氮的同化或减少底物NH向NH的转化实现的。因此，EM堆肥发酵可用于提高黑水虻幼虫在常见工业废物流上的性能并减少相关排放。
