Correct answer: (1) Candida krusei

Detailed Explanation

Candida krusei in Coffee Fermentation

• Candida krusei is a prevalent yeast species in the natural, spontaneous fermentation of coffee beans, actively participating in mucilage breakdown and influencing coffee flavor and quality.​

• Yeasts in the genus Candida (including C. krusei), Saccharomyces, and Pichia are critical during wet processing, especially at early fermentation stages.

Other Options

• Erwinia dissolvens: This bacterium is not a characteristic participant in coffee fermentation; it’s not documented as an important player in coffee processing. It is more often associated with plant diseases and the breakdown of pectin in some foods than with coffee fermentation.

• Lactobacillus delbrueckii and Lactobacillus plantarum:
  These lactic acid bacteria can participate in coffee fermentation, but they are not the principal or classic yeast agents. While L. plantarum may play a supporting role, especially late in fermentation, Candida krusei is a better match for a widely recognized coffee fermentation starter.