Parchami Milad, Uwineza Clarisse, Ibeabuchi Onyinyechi H, Rustas Bengt-Ove, Taherzadeh Mohammad J, Mahboubi Amir
Swedish Centre for Resource Recovery, University of Borås, 501 90 Borås, Sweden.
Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, Box 7024, Uppsala, Sweden.
Waste Manag. 2023 Oct 1;170:62-74. doi: 10.1016/j.wasman.2023.07.032. Epub 2023 Aug 5.
Volatile fatty acids (VFAs) supplementation in ruminants' diet as a source of energy and chemical precursors and their effect on animal's physiology and well-being has long been of scientific interest. Production of VFAs through anaerobic digestion of agro-industrial residues not only creates value but also presents an alternative sustainable approach for ruminant feed supplementation. Therefore, this study aimed to investigate the bioconversion of agro-industrial residues produced in large quantities such as apple pomace (AP), thin stillage (Ts), and potato protein liquor (PPL) to VFAs, fully complying to regulations set for ruminant feed supplement production. In this regard, batch acidogenic fermentation assays (pH 6-10) and semi-continuous immersed membrane bioreactor (iMBR) were applied. In batch assays, at pH 10 the co-digestion of Ts and PPL produced the highest VFAs concentration (14.2 g/L), indicating a yield of 0.85 g COD/g volatile solids (VS). The optimum batch condition was then applied in the iMBR for in situ fermentation and recovery of VFAs at different organic loading rates (OLR). With increasing the OLR to 3.7 gVS/L.day, the highest VFAs concentration of 28.6 g/L (1,2 g COD /gVS) was achieved. Successful long-term (114 days) membrane filtration was conducted in a media with a maximum of 40 g/L of total solids (TS), facing irreversible membrane fouling in the final stages. Acidogenic fermentation using an iMBR has the potential to play an important role in the future of feed additive provision through the biorefining of agro-industrial wastes via the carboxylate platform, given the role of VFAs production from organic residues.
在反刍动物日粮中添加挥发性脂肪酸（VFAs）作为能量和化学前体的来源，及其对动物生理和健康的影响，长期以来一直是科学研究的热点。通过厌氧消化农业工业残渣来生产VFAs，不仅能创造价值，还为反刍动物饲料补充提供了一种可持续的替代方法。因此，本研究旨在调查大量产生的农业工业残渣，如苹果渣（AP）、稀酒糟（Ts）和马铃薯蛋白液（PPL）向VFAs的生物转化，完全符合反刍动物饲料补充剂生产的规定。在这方面，采用了分批产酸发酵试验（pH 6 - 10）和半连续浸没式膜生物反应器（iMBR）。在分批试验中，在pH 10时，Ts和PPL的共消化产生了最高的VFAs浓度（14.2 g/L），表明产率为0.85 g COD/g挥发性固体（VS）。然后将最佳分批条件应用于iMBR，以在不同有机负荷率（OLR）下原位发酵和回收VFAs。随着OLR增加到3.7 gVS/L·天，实现了最高VFAs浓度为28.6 g/L（1.2 g COD /gVS）。在总固体（TS）最高为40 g/L的培养基中成功进行了为期114天的长期膜过滤，但在最后阶段面临不可逆的膜污染。鉴于有机残渣产生VFAs的作用，使用iMBR进行产酸发酵有可能通过羧酸盐平台对农业工业废物进行生物精炼，在未来饲料添加剂供应中发挥重要作用。
