Haouas Ayoub, El Modafar Cherkaoui, Douira Allal, Ibnsouda-Koraichi Saâd, Filali-Maltouf Abdelkarim, Moukhli Abdelmajid, Amir Soumia
Laboratoire Polyvalent en Recherche et Développement, Faculté Polydisciplinaire, Université Sultan Moulay Slimane, Beni Mellal, Morocco.
Laboratoire d'Agrobiotechnologie et Bioingénierie, Faculté des Sciences et Techniques, Université Cadi Ayyad, Marrakech, Morocco.
Saudi J Biol Sci. 2021 Jan;28(1):371-379. doi: 10.1016/j.sjbs.2020.10.015. Epub 2020 Oct 15.
The isolation and identification of beneficial bacteria from the active phase of composting is considered to be a key bio-quality parameter for the assessment of the process. The aim of this work was the selection and identification of beneficial bacteria from a co-composting experiment of vegetable waste (VW), olive oil mill waste (OMW), and phosphate sludge (PS). Phosphate-solubilizing strains were isolated from the thermophilic phase using Pikovskaya (PVK) solid medium supplemented with tricalcium phosphate Ca3(PO4) (TCP) as the sole source of phosphorus (P). Therefore, the selected isolate GTE53 was tested to tolerate abiotic stresses (different levels of temperature, variable pH, high salinity and water stress). The isolate was also assessed for indole acetic acid (IAA) and siderophores synthesis, nitrogen fixation, phenol degradation and pathogens inactivation. The quality of the co-composting process was also investigated by monitoring the physico-chemical parameters. The obtained results showed that GTE53 displayed a higher solubilization index of 2.4 and was efficiently dissolved, up to 162.8 and 247.4 mg·mL of inorganic phosphate from PS and phosphate rock (PR), respectively. GTE53 exhibited siderophores and IAA release, along with atmospheric nitrogen fixation. In addition to that, GTE53 showed a high resistance to heat and tolerance to acidic and alkaline pH, high salinity and water stress. Moreover, GTE53 could degrade 99.2% of phenol from a high-concentrated medium (1100 mg·L of phenol) and can inactivate the most abundant pathogens in industrial wastes: , sp., sp., and . Analysis of temperature, pH, electrical conductivity, carbon/nitrogen (C/N) ratio, indicated successful co-composting. An efficient transformation of P to the available form and a great abatement of polyphenols, were also recorded during the process. The findings of this study will help to advance the understanding of GTE53 functions and will facilitate its application to promote beneficial microbial organisms during composting, thus obtaining a high-quality product.
从堆肥活性阶段分离和鉴定有益细菌被认为是评估该过程的关键生物质量参数。本研究的目的是从蔬菜废弃物（VW）、橄榄油厂废弃物（OMW）和磷酸盐污泥（PS）的共堆肥实验中筛选和鉴定有益细菌。使用添加磷酸三钙Ca3(PO4)（TCP）作为唯一磷源（P）的皮科夫斯卡娅（PVK）固体培养基，从嗜热阶段分离解磷菌株。因此，对所选菌株GTE53进行了耐受非生物胁迫（不同温度水平、可变pH值、高盐度和水分胁迫）的测试。还评估了该菌株的吲哚乙酸（IAA）和铁载体合成、固氮、苯酚降解和病原体灭活能力。通过监测物理化学参数，对共堆肥过程的质量进行了研究。所得结果表明，GTE53的溶解指数较高，为2.4，能有效溶解PS和磷矿（PR）中的无机磷，分别达到162.8和247.4mg·mL。GTE53表现出铁载体和IAA释放，并具有大气固氮能力。此外，GTE53对热具有高抗性，对酸性和碱性pH值、高盐度和水分胁迫具有耐受性。此外，GTE53可以从高浓度培养基（1100mg·L苯酚）中降解99.2%的苯酚，并能使工业废物中最常见的病原体失活： 、 、 、 。温度、pH值、电导率、碳/氮（C/N）比分析表明共堆肥成功。在该过程中，还记录到磷有效转化为可用形式以及多酚大量减少。本研究结果将有助于加深对GTE53功能的理解，并将促进其在堆肥过程中应用以促进有益微生物的生长，从而获得高质量的产品。
