Glycerin

One gram of soil per sample was used to cultivate and count different soil microorganisms: total viable aerobic mesophilic bacteria count (TVA) was made with Plate Count Agar (Scharlau, Barcelona, Spain) at 28 °C for 48 h, total molds and yeast count (TMY) with Saboureaud Chloramphenicol Agar (Scharlau, Barcelona, Spain), at 28 °C for 3 d, total strictly anaerobic bacteria count (Tan) with Schaendler Agar (Conda Pronadisa, Madrid, Spain) at 37 °C in CO₂ atmosphere for 48 h, and total oligotrophic bacteria count (TO) with Oligotrophic Agar, composed of dipotassium phosphate (Panreac, Barcelona, Spain), magnesium sulfate heptahydrate (Panreac, Barcelona, Spain), peptone (Scharlau, Barcelona, Spain), glycerin (Scharlau, Barcelona, Spain), and bacteriologic agar (Labkem, Dublin, Ireland) [83 ] at 28 °C, 5 d. All the analyses were performed in duplicate. Results were expressed in log CFU/g of soil.

The native potato (Solanum tuberosum subsp. Andigena) was collected from crop fields of the Centro Poblado Huancas, which is located in the district of Andarapa, Andahuaylas, Peru (13°40′42″ S, 73° 15′11″ W, and 3742 m of altitude), in the vegetative period from October 2020 to March 2021.
The corn wastes (husks) were collected from fields in the district of Andahuaylas, Peru (13°39′12″ S, 73°23′22″ W, and 2953 m of altitude), in the vegetative period from September 2020 to May 2021.
Chemical substances were used, such as glycerin (99% purity, food grade), anhydrous citric acid (99.5% purity), sodium hydroxide (98.5% purity), potassium permanganate (99.0% purity), acetic acid (99.8% purity), ethanol (96.9% v/v) from the Scharlau brand (Barcelona, Spain); also, sodium hypochlorite (14% solution), phenolphthalein and potassium bromide (IR Grade) of the Merck brand (Darmstadt, Germany).