Bensmail Souhila, Boudjema Khaled, Naimi-Fazouane Fethia, Bensmail Samira, Djouahra-Fahem Djamila, Ferhoum Fatiha, Bourfis Nassima
Department of Biology, Faculty of Nature and Life Sciences and Earth Sciences, Akli Mohand Oulhadj University, Bouira, Algeria.
Research Laboratory of Food Technology, M'hamed Bougara University, Boumerdes, Algeria.
BioTechnologia (Pozn). 2023 Dec 21;104(4):333-349. doi: 10.5114/bta.2023.132770. eCollection 2023.
The exploitation of food industry wastes and their conversion into value-added products present a promising and continuously growing field, given the diversity of elaborated wastes. The current work aimed to utilize sweet cheese whey as a growth medium for acid protease production by a local fungus strain. The biochemical and physicochemical properties of the cheese whey, such as pH, conductivity, chemical oxygen demand, biological oxygen demand (BOD), total nitrogen and protein contents, and mineral salts, were assessed using various analytical methods. The effect of certain parameters on acid protease production by MG603064.1 through the SmF process was investigated using the conventional design method "One factor at a time". Subsequent to characterization, the crude extract was used in a trial to create , compared to the commercial rennin CHY-MAX Powder Extra. Cheese whey characterization revealed its richness in total nitrogen (1.044 ± 0.044 g/l), protein content (6.52 ± 0.04 g/l), and principal mineral salts: calcium (1.637 ± 0.037 g/l), phosphorus (1.173 ± 0.023 g/l), and chloride (1.66 ± 0.09 g/l). The optimal values of the SmF process for acid protease production, such as the inoculum size, beef extract, and KHPO supplements, the initial pH of cheese whey, and incubation temperature were, respectively, 11% (v/v), 0.4% (w/v), 0.5% (w/v), 5.5, and 30°C. Under these conditions, the lowest milk-clotting time of 290 s was achieved, representing an 18.41-fold increase compared to the initial step using the unoptimized medium. The enzyme showed maximum milk-clotting activity at pH 5, a temperature of 60°C, and in the presence of 0.025 M of CaCl. The enzyme activity also significantly improved with sonication (35 kHz) for 10 min. The crude extract of ensured the production of fresh cheese samples with characteristics roughly similar to those obtained by the control (CHY-MAX rennin). The acid protease of could successfully substitute the conventional rennin in the manufacture of fresh cheese.
鉴于加工废弃物的多样性，食品工业废弃物的开发利用及其转化为增值产品是一个前景广阔且不断发展的领域。当前的工作旨在利用甜奶酪乳清作为本地真菌菌株生产酸性蛋白酶的生长培养基。使用各种分析方法评估了奶酪乳清的生化和物理化学性质，如pH值、电导率、化学需氧量、生物需氧量（BOD）、总氮和蛋白质含量以及矿物盐。采用传统的“一次一个因素”设计方法，研究了某些参数对MG603064.1通过固态发酵（SmF）过程生产酸性蛋白酶的影响。在进行表征之后，将粗提取物用于试验以制作奶酪，与市售凝乳酶CHY-MAX Powder Extra进行比较。奶酪乳清表征显示其富含总氮（1.044±0.044 g/l）、蛋白质含量（6.52±0.04 g/l）以及主要矿物盐：钙（1.637±0.037 g/l）、磷（1.173±0.023 g/l）和氯（1.66±0.09 g/l）。固态发酵过程中生产酸性蛋白酶的最佳值，如接种量、牛肉提取物和KHPO补充剂、奶酪乳清的初始pH值以及培养温度，分别为11%（v/v）、0.4%（w/v）、0.5%（w/v）、5.5和30°C。在这些条件下，实现了最低凝乳时间290秒，与使用未优化培养基的初始步骤相比增加了18.41倍。该酶在pH 5、温度60°C以及存在0.025 M CaCl的情况下表现出最大凝乳活性。超声处理（35 kHz）10分钟也显著提高了酶活性。粗提取物确保了新鲜奶酪样品的生产，其特性与对照（CHY-MAX凝乳酶）获得的特性大致相似。MG603064.1的酸性蛋白酶可以成功替代传统凝乳酶用于新鲜奶酪的制造。
