The earliest ancestors I know from this line in Alfeld are C. Frederich Bauche and his wife Augusta Kreibaum. I have no birth dates on either, but their son Carl August Wilhelm Bauche was born 3 Mar 1829 (in Alfeld). That puts their birth dates around 1790-1810. I had not been able to find any other instance of the name "Bauche" anywhere in Germany.