Sidari R, Caridi A
Dipartimento di Scienze e Tecnologie Agro-Forestali e Ambientali, Università degli Studi Mediterranea di Reggio Calabria, Reggio Calabria, Italy.
Folia Microbiol (Praha). 2009;54(3):230-2. doi: 10.1007/s12223-009-0036-3. Epub 2009 Aug 2.
Glycerol-based medium (BM) with and without the addition of 1 g/L ascorbic acid (Asc) and/or 100 mg/L (+/-)-catechin (Cat) was tested for the storage of three commercial wine yeasts at -20 degrees C. The medium supplemented with Asc was also used to store 706 strains to verify the maintenance of the liquid state. A decline in survival throughout the storage period was observed. The media containing Asc maintained viability better than the other three. The BM caused a loss of viability of 7 orders for one strain and of 6 orders for the other two. All three strains exhibited a loss of viability of 4 orders when stored in BM+Asc. Two strains decreased viability by 5 orders while one strain by 4 orders, when stored in BM+Cat. Two strains decreased viability by 6 orders while one strain by 5 orders, when stored in BM+Asc+Cat. Regarding the physical state of the medium tested on 706 yeast strains, three cases were observed: completely liquid (56.5 %), liquid with only the upper part frozen (40.4 %) without involving the yeast biomass settled at the bottom, and completely frozen (3.12 %). It is practicable to prepare a BM that remains liquid at -20 degrees C enhancing yeast viability when Asc is added as cryoprotectant.
在甘油基培养基（BM）中添加或不添加1 g/L抗坏血酸（Asc）和/或100 mg/L（±）-儿茶素（Cat），测试其在-20℃下对三种商业葡萄酒酵母的保存效果。添加了Asc的培养基也用于保存706株酵母，以验证其液态的维持情况。在整个保存期间观察到存活率下降。含有Asc的培养基比其他三种培养基能更好地维持酵母的活力。BM使一种菌株的活力损失了7个数量级，另外两种菌株的活力损失了6个数量级。当保存在BM+Asc中时，所有三种菌株的活力均损失了4个数量级。当保存在BM+Cat中时，两种菌株的活力下降了5个数量级，一种菌株下降了4个数量级。当保存在BM+Asc+Cat中时，两种菌株的活力下降了6个数量级，一种菌株下降了5个数量级。关于在706株酵母菌株上测试的培养基的物理状态，观察到三种情况：完全呈液态（56.5%）、仅上部冻结的液态（40.4%），且不涉及底部沉淀的酵母生物质，以及完全冻结（3.12%）。制备一种在-20℃下仍保持液态的BM是可行的，当添加Asc作为冷冻保护剂时可提高酵母的活力。
