Production of <FONT FACE=Symbol>a</FONT>-amylase in acid cheese whey culture media with automatic pH control

Abstract

The influence of aeration and automatic pH control on the production of &lt;FONT FACE="Symbol"&gt;a&lt;/FONT&gt;-amylase by a strain of Bacillus subtilis NRRL 3411 from acid cheese whey was studied. Tests were carried out in a rotary shaker and in mechanically stirred fermenters. &lt;FONT FACE="Symbol"&gt;a&lt;/FONT&gt;-amylase was analysed according to DUN’s method. Oxygen absorption rate was determined by Cooper’s method. Cell oxygen demand was determined as oxygen consumption in a Warburg respirometer. The level of dissolved oxygen was measured by means of a galvanic silver-lead electrode. Results suggest the possibility of industrial use of acid cheese whey as a carbon source for &lt;FONT FACE="Symbol"&gt;a&lt;/FONT&gt;-amylase production, since the yield was similar to that produced with lactose. The highest &lt;FONT FACE="Symbol"&gt;a&lt;/FONT&gt;-amylase levels 10,000 DUN/ml units were not attained at higher aeration rates -431 mLO2/L.h-. The indicated value correspond to a 96 h process with automatic pH control at 7.5. These conditions resulted in double concentration of &lt;FONT FACE="Symbol"&gt;a&lt;/FONT&gt;-amylase. The enzyme production was directly related to growth in the form of cell aggregates.

Comparison of two lipid extraction methods produced by yeast in cheese whey

“…Several co-products and raw materials for food industry and agroindustry have been used to obtain biotechnological products because of their high availability, which represents an alternative source of low commercial value (Silva et al 2009;Ernandes et al 2010). Cheese whey is one of the most abundant by product, which can be employed for the development of various value-added products such as ethanol (Dragone et al 2011;Koushki et al 2011), fatty acid methyl esters (Takakuwa and Saito 2010), biopolymer poly (3-hydroxybutyrate) (Nickel et al 2005), biosurfactants (Rodrigues et al 2006), xanthan gum (Silva et al 2009), bacteriocins (CladeraOlivera et al 2004), lactic acid (Ghasemi et al 2009), citric acid (El-Samragy et al 1996, gluconic acid (Chaturvedi et al 1999), α-amylase (Ferreyra et al 1998), β-galactosidase (Santiago et al 2004;Manera et al 2011) and manganese peroxidase (Feijoo et al 1999). After increase to 18% in exports of cheese in 2010, it is estimated that EU exports for 2011 and 2012 would continue to grow, even for the U.S. where cheese production is projected to expand in 2011 to 4.8 million tons, an increase of 3% to a record 4.9 million tons in 2012.…”